STORMWATER MANAGEMENT AND RECREATIONAL MASTER A …

STORMWATER MANAGEMENT AND RECREATIONAL MASTER

PLAN FOR SOUTH AND SOUTHWEST LUBBOCK

by

MARK A. RICH, B.S.

A THESIS

IN

LANDSCAPE ARCHITECTURE

Submitted to the Graduate Faculty of Texas Tech University in

Partial Fulfillment of the Requirements for

the Degree of

MASTER OF LANDSCAPE ARCHITECTURE

Approved

Accepted

Dearyôf the Graduate /School

May, 1998

/ - ' , ACKNOWLEDGEMENTS ; ^ ' (•

(Oo- ^^

i oC • '^^ I would like to thank everyone whose contributions have made this thesis possible.

Special acknowledgement is due my committee chairman, John Billing, whose patience,

understanding, and encouragement enabled me to stay on course to completion of this

thesis. Also, I would like to thank Dr. Emest Fish for providing access to ARC/INFO and

directing my efforts in analyzing urban hydrology information, and Thomas Musiak,

Chair and Professor of the Department of Landscape Architecture, for providing helpful

insights and comments which enhanced the final outcome.

Credit must also be given to Randy Henson, Senior Planner for the City of Lubbock,

who planted the seed for this thesis topic. 1 would also like to thank Larry Hertel, P.E.,

City Engineer, Keith Smith, P.E. and Skipper Woods, P.E. of the City of Lubbock

engineering staff who unselfishly provided access to files and information regarding the

playa lakes in my study area.

Finally, and most importantly, I must thank my family for their patience as I pursued

this goal.

K C

11

TABLE OF CONTENTS

ACKNOWLEDGEMENTS ii

LIST OF TABLES \

LIST OF FIGURES vii

CHAPTER

I. INTRODUCTION 1

Definition of Problems 1

Landscape Plan Suppositions 3

The Delimitations 3

Definition of Terms 4

Abbreviations Used in the Thesis 5

Thesis Assumptions 6

The Importance of the Study 6

II. REVIEW OF THE RELATED LITERATURE 8

Stormwater Management 8

Electromagnetic Fields 16

Open Space/Parks 20

III. METHODOLOGY 22

111

IV. MASTER PLAN DISCUSSION 32

Introduction 32

Individual Site Plan Discussion 36

V. MASTER PLAN SUMMARY AND RECOMMENDATIONS 94

LITERATURE CITED 98

APPENDIX: WATERSHED CALCULATIONS 99

IV

LIST OF TABLES

1. Runoff Curve Numbers for Urban Areas 26

2. Watershed No. 1 29

3. Watershed No. 1 Worksheet 30

4. Proposed Land Uses, Zone 1 40













17. Soil Types and Coverage, Watershed No. 2 100




21. Soil Types and Coverage, Watershed No. 4 1 < >4







28. Watershed No. 9 Worksheet I l l
















VI

LIST OF FIGURES

1. Rainfall Distribution Map 25

2. Watershed Boundaries 28

3. Master Plan Zone 1 39













Vll

CHAPTER 1

INTRODUCTION

There exists a landscape corridor just outside the southern limits of the city of

Lubbock which, in a few years, will likely be included within the Lubbock cit\ limits.

The boundaries of this particular landscape corridor are 98th Street on the north. Farm to

Market (FM) 1585 on the south, Upland Avenue on the west, and US Hwy 87 on the east

comprising an area of approximately 14.8 square miles (9,472 acres). For purposes of

this study, the landscape is divided into thirteen zones with each zone delineated by the

existing grid sectional road layout. Although Lubbock is located in the Southern High

Plains region of Texas, a region characterized by little topographic relief, the

forementioned landscape poses unusual stormwater management issues for development

because one of the seventeen playa lakes within the study area is unusually large. There,

also, are high-voltage electrical transmission lines within a sixty foot wide electric utility

easement running east to west through the corridor.

Definifion of Problems

There are three problems inherent with planning and development of this corridor:

(1) the quantity and quality of stormwater mnoff to each playa basin, (2) the alleged

public health effects resulting from exposure to the electrical transmission line and its

accompanying electro-magnetic field (EMF), and (3) designing areas for recreation and

open space to meet the anticipated needs of any new development.

Concerning playa lakes, Zartman and Fish (1992) state that playas pro\ ide "storage

for most surface runoff (p. 62). The reauthorization of the Clean Water Act in 1987

effectively mandated that non-point source pollution become a high priority issue . which

in tum reemphasized what Zartman, Evans, and Ramsey (1994) termed "Ihe controversial

concept of playas as wetlands" (p. 299). According to Zartman, et al., "playa wetlands

are important to ground water recharge in the Southern High Plains and pollutants

entrained in the playa lake mnoff water may eventually contaminate the ground water" (p.

301). The challenges are to allow development that is compatible with the current City of

Lubbock Comprehensive Land Use Plan (1986), and manage surface runoff so that water

retained in each playa lake meets quality standards as required by Environmental

Protection Agency (EPA) regulations under the 1987 Nafional Pollutant Discharge

Elimination System (NPDES) permitting program for urban storm drainage systems.

The 115 kilovolt (kV) transmission line running east to west through the study area

and its accompanying electro-magnetic field is a factor that needs to be addressed prior to

development of the area. Horton and Goldberg (1995) assert that:

Despite the failure of more than forty studies of disease in the populations of industrialized countries to conclusively prove a connection between magnetic field exposure and adverse health effects, particularly cancer, the magnetic field issue has in recent years become an area of increasing public concern. That concem is in response to studies "linking'" magnetic field exposure to cancer. (A prime example is the 1992 Swedish study which found that children living near power lines had about four times the leukemia rate of other children.) (p. 2)

According to the 1986 Lubbock Comprehensive Land Use Plan, playas, or dry lakes,

should be viewed as an aesthetic amenity; natural drainage areas should be utilized as

park sites; open space resources should be beautified and developed to help create a

unique image. Therefore, the relationship between de\ elopment and pla\ a basins as

parks/open space will be considered.

Landscape Plan Suppositions

1. The first supposifion. The first supposition is that non-point runoff can be

effectively controlled and treated by natural infiltration processes.

2. The second supposition. The second supposition is that the public is not exposed to

unreasonable health risks when in the proximity of high-voltage electrical transmission

lines.

3. The third supposition. The third supposition is that a land-use master plan can be

developed illustrating open space/park areas while also addressing stormwater

management and the high-voltage electrical transmission line.

The Delimitations

The thesis is limited to the study area which is outside the present cit\ limits of

Lubbock, comprising an area of approximately 8,093 acres compared to the

approximately 9,472 acres contained within the entire study area.

The land-use master plan is a concept plan. It is subjective in nature rather than

objective. It is not intended as a detailed landscape design or engineered design.

The thesis includes existing residential and commercial land uses e\ en though the\

may not coincide with the current City of Lubbock Comprehensi\ e Land Use Plan.

Calculations of stormwater mnoff volume are based on the stud\ area being in a full\

developed condition consistent with the City of Lubbock Land Use Plan of 1986 which

projects the majority of land use to be low density residential with smaller areas of

medium density residential, high density residential, and commercial land uses.

The thesis does not attempt to address all methods of stormwater control, such as

storm sewers.

The 100-year flood elevation of each playa basin was determined soleh on the

capacity required to accommodate a 100-year event and does not take into account factors

such as future possible reduction of existing playa volume due to sedimentation or

modification.

Issues in EMF research such as in vitro (test tube) studies at the cellular le\ el are not

addressed in this thesis.

Definitions of Terms

Acre-feet is the quantity of water (43,560 cubic feet) that would co\er one acre to a

depth of one foot.

Detention "refers to any type of storage of excess runoff on a site prior to its discharge

into dovsoistream drainage systems and gradual release of the temporarily stored mnoff

after the peak of the mnoff inflow has passed" (Wanielista, 1991, p. 167).

Infiltration as it relates to stormwater is the directing of urban runoff a\va\ from

surface discharge and into the underlying soil.

Playa is "an ephemeral lake that is located within a topographically closed basin in this

area" (Zartman et al., 1994, p. 299).

Retention refers to storing or keeping stormwater. as in a basin, so that it is released

into the soil by infiltration and percolation; and, into the atmosphere by evaporation.

Abbreviations Used in the Thesis

The following abbreviations are used in this thesis:

Ac. is the abbreviation for acre(s).

BMP is the abbreviation for Best Management Practice.

CN is the abbreviation for mnoff curve number.

DOE is the abbreviation for the U.S. Department of Energy.

EPRI is the abbreviation for the Electric Power Research Institute.

EMF is the abbreviation for electro-magnetic field(s).

EPA is the abbreviation for the U.S. Environmental Protection Agenc\.

FM is the abbreviation for Farm to Market Road.

HSG is the abbreviation for Hydrologic Soil Group.

kV is the abbreviation for kilovolt.

NA is the abbreviation for Not Applicable.

NPDES is the abbreviation for the National Pollutant Discharge Elimination System.

NRC is the abbreviation for the National Research Council.

NRCS is the abbreviation for the Natural Resources Conservation Ser\ ice.

NRPA is the abbreviation for the National Recreation and Park Association.

PUC is the abbreviafion for the Public Utility Commission of Texas.

TR 55 is the abbreviafion for NRCS Technical Release 55, Urban Hydrology for Small Watersheds, 2nd Edition.

VBS is the abbreviation for vegetative buffer strip.

Thesis Assumptions

There are three assumptions inherent in this study:

The first assumption. The first assumption is that management of stormwater quantitv

and quality will be necessary as the proposed study area is developed; and that surface

drainage of stormwater is the most economical altemative for the City of Lubbock to

pursue.

The second assumption. The second assumption is that the issue of latent negative

health effects related to EMF will need to be resolved before the proposed stud\ area is

fully developed.

The third assumption. The third assumption is that areas for recreation and open space

will need to be contemplated prior to urban development taking place in the proposed

study area.

The Importance of the Studv

The reauthorization of the Clean Water Act in 1987 mandated regulations for control

of non-point sources of pollution. This has become a major concem for the City of

Lubbock because there are several playa lakes in the city where the water quality does not

conform to EPA standards. As a result, the Lubbock City Council established the Pla\ a

Lake/ Drainage Study Committee in May 1989. One of the Committee recommendations

was for the City to initiate preparation of a "Master Drainage Plan". In November 1994 a

contract with Parkhill, Smith, and Cooper, Inc., Engineers, Architects, and Planners was

entered into to prepare the NPDES permit for the City of Lubbock to submit to the EP.\.

Also, Parkhill et al. were to prepare a base map of projected 100-year flood levels of

various playa lakes that may be included in future city expansion. The need for

stormwater control methods that are more effective than what have been historicalh used

in Lubbock is a necessity considering today's regulatory climate.

According to Horton and Goldberg (1995):

Since 1979 the magnetic field issue has become an area of increasing public concem. The concem over power frequency magnetic fields began with a case controlled epidemiological study of childhood leukemia, carried out by Wertheimer and Leeper in Denver, Colorado, in 1979. Until that study, there had been no evidence of a relationship between ver> low energy fields and human health. While the Wertheimer and Leeper study has been amply criticized for its design and methodology, it must also be recognized as an historical tuming point. [Since the study,] the public has shown heightened sensitivity to the siting of new, and redesign of existing, electric facilities. Much of this sensitivity centers on the exposure to magnetic fields and their potential impact on human health. The introduction of nearly every new transmission line is being challenged b\ the public because of concems over possible health effects from the exposure to the magnetic fields associated with such lines, (pp. 5-6)

Therefore, the EMF research data that are currently available were studied so that

relatively informed decisions were made conceming the relationship between high-

voltage electrical transmission lines and adjacent development.

It is a goal of the current Comprehensive Land Use Plan to develop recreational

properties which will enhance the aesthetic quality of life in Lubbock (Lubbock 2005

Goals).

CHAPTER II

REVIEW OF THE RELATED LITERATURE

Stormwater Management

Introduction

Field, O'Shea, and Chin (1993) contend that:

Land management includes stmctural, semi-stmctural, and nonstructural measures for reducing urban and constmction site runoff and pollutants before they enter the downstream drainage system.

Tradifional urbanization upsets the natural hydrologic and ecological balance of a watershed, (p. 16)

Ferguson (1991) further states that "urbanization involves the sealing of the land

surface with pavements and roofs, creating a hydrologically new kind of landform "

(p. 25). Field et al. state that "the degree of upset depends on the mix, location, and

distribution of the proposed land use activities. As man urbanizes, the receiving waters

are degraded by mnoff from his activities" (p. 16).

According to Ferguson:

Urban impervious surfaces alter all parts of the hydrologic balance. They deflect rain water away from infiltration, soil moisture, recharge, subsurface storage and base flow. Impervious surfaces prevent water from entering the natural structures and processes that maintain hydrologic storages and moderate hydrologic flows. The deflection away from subsurface paths creates mnoff that moves quickly down stream systems and out of the landscapes where it originated. This effect is reflected in storm flow rate and volume, (p. 25)

Mankind's clearing, paving, damming and channelization have often been done with the intent of subduing and controlling nature, but instead have bound nature's dynamic mechanisms into distorted cycles of erosion, extinction and stress. While accommodating human use, the natural operation of environmental adjustment mechanisms should not be

8

restricted. If our sense of the hydrologic continuum is fragmented, then our water management will follow in the same path. (p. 31)

Field et al. (1993) believe that "the goal of urban development resources planning is a

macroscopic management concept to prevent problems from shortsighted planning. New

variables of land usage and its perviousness, population density, and total runoff control

must be considered and integrated with desired water quality by land-use planners"

(p. 16). Ferguson (1991) expressed his opinion that "our understanding of urban

hydrology must encompass vegetation and evapotranspiration as well as imper\ious

surfaces and direct mnoff. It needs to address long-term storage in subsurface voids as

well as the visible dynamism of surface flows" (p. 31).

Urban stormwater mnoff, according to Field et al. (1993):

... has been recognized as one of the major nonpoint sources of pollufion, contribufing to the degradafion of water quality in receiving-water bodies. Characterisfics of urban storm runoff and its impact have been well documented. However, urban stormwater pollution control measures are still in the eariy stages of implementafion and relatively few performance data are available from full-scale field applications. Such performance data are needed for the derivation of design criteria for the various structural control measures or "Best Management Practices"(BMPs). (p. 191)

Natural drainage will reduce drainage costs and pollution, and enhance aesthetics, groundwater supplies, and flood protection. A project near Houston, Texas, The Woodlands, focused on how a "natural-drainage system" integrates into a reuse scheme for recreation and aesthetics. Runoff flows through vegetative swales and into a network of wet-weather ponds, strategically located in areas of porous soils. This system retards the flow of water downstream, preventing floods by development, and enhances pollution abatement, (p. 16)

Porous Pavement

"An interesfing technological answer to the problem of preserving perv ious areas is

using an open-graded asphaltic-concrete. known genericallv as porous pavement, as a

paving material" (Field et al.. 1993. p. 16).

Field et al. continue:

The resulting paving has a coarse texture and a high v oid ratio resulting in temporarv storage of surface water while maintaining the coefficient of friction between a vehicle tire and pavement at v alues comparable to the coefficient under dry conditions, (p. 151)

Porous pavements provide storage, enhancing soil infiltration that can be used to prevent mnoff. Porous asphalt-concrete pavements can be underlaid by a gravel base course with whatev er storage capacity is desired, (p. 17)

Although porous pavements can store a percentage of mnoff. it should be remembered

that in the Southem High Plains airbome dust and sand will settle into the surface v oids

of the pavement and may potentially reduce storage capacity. Even so. there arc smaller

V oids between the sand particles that can permit infiltration. Another factor is that oils

and other fluids that leak from automobiles can accumulate on the pav ement and bind

with the V arious aggregates to create a barrier between stormwater and the pavement.

Even if this occurs, pollutants may be retained on the aggregate surfaces rather than

transported to the playa.

Field et al. report that:

Information on water qualitv benefits of porous pavements are limited. However, significant pollutant loading reductions have been observed bv. e.g.. Pratt et al. and Hogland et al. (p. 197)

Also, results from a study in Rochester. New York indicate that peak mnoff rates were reduced as much as 83%. The structural integrity of the porous pavement was not impaired by heavy-load vehicles. The

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construction cost of a porous pavement parking lot is about equal to that o( a conventional paved lot with stormwater inlets and subsurface piping, (p. 17)

Parking lots consisting of concrete lattice blocks with grass planted in the interstices are an aesthetic and practical solution to urban stormwater drainage and detention. This approach also allows for storage of runoff in the low areas within the blocks, and permanently removes that volume of water from surface discharge. Furthermore, the grass may provide an added benefit in being able to recycle nutrients and other mnoff constituents.

Porous pavements can be designed to retain all of the rainfall and runoff with no drainage from the site, to retain sufficient rainfall and runoff to reduce the after-development hydrologic conditions to predevelopment conditions, or to delay mnoff from the site, thus attenuating peak discharges and reducing the impact of associated pollutant transport, (p. 151)

Sanitation

"Surface sanitation by maintaining and cleaning urban areas can have a significant

impact on the quantity of pollutants washed off by stormwater with secondary benefits of

a cleaner and healthier environmenf' (Field et al., 1993, p. 17). Surface sanitation is a

method which can be used to enhance the effectiveness of porous pavements.

nptpntion Ponds

The concept of using stormwater detenfion basins to reduce runoff pollution gained

widespread attention as a result of studies authorized under Section 208 of the 1972

Clean Water Act established by the U.S. Congress. The "dual-purpose" detention pond

design approach allows the pond to reduce flood damages downstream and reduce

nonpoint pollution from storm mnoff The EPA Nationwide Urban Runoff Project

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further demonstrated the water quality benefits of wet detention basins (Field et al..

1993). Multipurpose detention/retention and drainage facilities, and other management

techniques required for flood and erosion control, can be simultaneouslv designed or

retrofitted for pollution control. Stormwater retention on-site or upstream can prov ide tor

the multi-benefits of aesthetics, recreation, recharge, irrigation, or other uses. Fhis

induces solid-liquid separation by settling and enables entrapped solids and floatables to

be disposed of at a later time without causing pollution downstream (Field et al.. 1993).

Dry ponds are depressed areas which store mnoff during storms. Thev are usual Iv

designed to reduce the peak flow resulting from a selected design storm (e.g., a lO-vear

storm) to the predevelopment level to prevent downstream flooding. However, drv ponds

are not very effective in removing pollutants; they are basically designed for controlling

quantity, not quality. Because of the short detention times, many particulate pollutants do

not have enough time to settle out of the mnoff, and the ones that do settle to the bottom

of the pond are very easily resuspended by the next storm event. Pollutant removal

efficiency for dry ponds reported in the literature ranged from 0% to 20% for all

pollutants as an average (Field et al., 1993).

Wet ponds, by maintaining a permanent pool, allow particulate pollutants to be

removed by biological uptake or other decay processes. For example, long-term average

removal estimates by Driscoll range from around 50 to >90% for total suspended solids

(TSS), 40 to 60% for nutrients, and 40 to 45% for zinc. Moderate to high removals for

wet ponds were also reported for studies in Florida, North Carolina, and Virginia (Field et

al., 1993).

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U'etlands

Wetlands have been used a long time for final treatment of municipal wastewater.

Wetlands are intricate ecosystems that are characterized bv' high floral productiv itv and

nutrient needs, high decomposition rates, low oxygen content in the sediments and

substrates, and large adsorptive surfaces in the substrates. Processes of wetlands that

remove pollutants include physical processes, such as sedimentation for particulate

pollutants; adsorption for ammonium ions, phosphate, metals and v imses; chemical

precipitation for metals; filtration for organic matter, phosphorous, bacteria, and solids;

V olatization for oils, chlorinated hydrocarbons, and mercurv: and biological processes

such as nutrient uptake (Field et al.. 1993).

Several studies have shown the cost-effectiveness of wetlands. However, using

wetlands to treat urban mnoff is a recent idea. Field et al. (1993) have reported that:

A study conducted in Minnesota by Barten (1981) examined the use of natural marshes to filter nutrient-rich urban mnoff water. Significant removal of nutrients and suspended solids was observed. However, verv little information is available regarding the cost-effecfiveness of using natural or artificial marshes as a Best Management Practice (BMP). \'erv little information is available regarding design criteria for wetlands used for stormwater treatment. The limited literature findings suggest that important factors to be considered in wetland design and management are pretreatment (for example, a detention pond before a wetland) for solids removal and wetland hydrology, (pp. 201-202)

T pvel Spreader/Vegetative Buffer Strip

A vegetative buffer strip(VBS) is a stormwater management practice which utilizes a vegetated surface to reduce mnoff velocities, allow infiltration, and filter out mnoff pollutants. The VBS has been found to be

13

a cost-effective control measure for reducing solids, nutrients, and other pollutants in stormwater mnoff. For example, Barfield and Albrecht (1982) reported that a VBS could remove approximately 70 to 99% of all fine grained sediment. More recenfiy, Dillaha et al. (1986) monitored VBS on 33 farms in Virginia to evaluate their long-term effectiv eness and water quality improvement. Among their findings, the most significant factor effecting the performance of VBS was the flow regime. They concluded that when water was allowed to achieve a concentrated flow profile, only minor pollutant reduction was achieved. However, good removal efficiencies for suspended solids and particulate nutrients were obtained when overiand flows were spread evenly across the filter strips.

Laboratory research was conducted in 1975 at the University of Kentucky on simulated grasses in order to gain a stronger understanding of the filtration dynamics of grasses. Conclusions were that grass filters provide excellent trapping efficiencies and that the establishment of grass filters is much more economical than the use of detention basins. A laboratory study by Kao in 1980 concluded that continuous flooding did not appear to reduce filtrafion efficiencies and that longer filter lengths would be needed if colloidal size particles were to be removed.

The level spreader is essentially an earthen trench placed on the contour and has a concrete weir spillway on the downslope side of the trench. Thus, the level spreader takes the concept of a vegetative buffer strip one step further by combining it with an infiltration trench and a concrete weir spillway for an enhanced method of stormwater pollution control. When a storm occurs, the discharge is routed into an infiltration trench, which serves as a miniature detention basin. Water fills this trench, and then flows over the concrete weir built in front of the trench and continues downslope through the VBS. Removal of stormwater pollution takes place in both the infiltrafion trench and in the VBS.

Mechanisms associated with the level spreaderA^BS system can be summarized as the following:

- settling which occurs in the level spreader itself - sedimentation and filtration, removing primarily solids and metals by the filter strip

- adsorpfion, plant uptake, and precipitafion, removing primarilv nutrients by the filter strip. (Field et al., 1993, pp. 93-94)

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Infiltrafion

Ferguson (1991) states that infiltration is "entrv of water from the ground surface into

the underlying earth material" (p. 16). When rainwater reaches the soil or when surtace

water flows down a small stream or ponds in a depression, some of the water sinks into

the soil. "The term infiltration contains the root of the word filter, meaning to pass

through: the prefix signifies that the process is one of passing into" (Ferguson, pp. 16-17).

Ferguson (1991) further posits that:

Stormwater infiltration addresses the cause of the urban stormwater problem at the soil surface where development takes place. Infiltration controls the volume of storm mnoff. keeping aggravated storm surges out of streams and retuming the flow volume to its place in the soil and long-term base flows. It uses the natural capacities of soil, vegetation and landforms for restoring the direction, timing and qualit\ of h> drologic flows. It promises to restore the hydrologic balance of urban landscapes, retuming hydrologic storages and flow regimes, and the ecosystems of which they are a part, to a self-sustaining equilibrium, (p. 31)

Infiltration has been used as the only means of stormwater management and in

combination with other stormwater management methods such as conv ev ance. detention

and wetland systems. The use of infiltration has prevented or solved problems of

flooding, storm sewer cost, water quality, wetland maintenance, and replenishment of

ground water and stream base flows. It has also been utilized in arid environments in

combination with water harvesting to reduce irrigation demands of urban plantings

(Ferguson, 1991).

Ferguson (1991) further explains that:

A well-vegetated upland soil can infiltrate water at surprisinglv high rates. Despite the predictions of some early hydrologic models, under

15

natural rainfall surface mnoff is almost never generated on well-vegetated unsaturated soils. In wooded or thickly grassed areas of the humid eastem United States, plants and organic litter cover the soil, protecting it from the erosive impact of falling raindrops. Vast amounts of rainwater are conveyed into the soil by macropores, built partly by plant roots and stabilized partly by decomposed organic matter. By the time rainwater reaches purely mineral soil, the water is working under vadose processes (water contained within the pores of soil and rock) in the soil matrix, and a large quantity of water has been stored in the surface layer for continued deeper percolation.

In contrast, mnoff occurs frequently on many unvegetated upland surfaces such as soils denuded by constmction, desert pavements and urban impervious surfaces. In such places the surface lacks a porous stmeture. Little infiltration occurs, and a large part of rainfall goes into direct surface mnoff.

Infiltrated water moves downward into soil, partly because it is pulled from below by the matric suction of underlying soil that is drier than that near the surface. Movement into a soil stops when the wetting has progressed so far that all the water that has been soaked into the soil is held by attraction to the grains and is in equilibrium with the matric suction of the surrounding soil. (p. 17)

As it is with other human endeavors, the objecfives of the project will define the

performance of stormwater infiltrafion in a given site development. Meaningful

stormwater management objectives should be based on an understanding of specific

conditions both within the boundaries of the site and in the broader landscape sv stems of

which the individual site is a part, including surrounding urban neighborhoods, upstream

and downstream watersheds and underiying landforms and soils (Ferguson. 1991).

F.lectromagnefic Fields

The Electro-Magnetic Health Effects Committee (subsequently referred to as the

Committee) in a report produced for the Public Utility Commission of Texas (PUC)

16

found that, "until recently, serious inquiry about biological effects associated w ith

electricity was limited to safety issues, primarily those identified w ith electrical shock"

(1992, p. l-l). The Committee also reported that there were several events which

occurred in the 1960's and 1970's that brought about investigation regarding the

biological effects of exposure to electric and magnetic fields (EMF). Reports that came

out of the Soviet Union in the early 1960's indicated that there was neurological and

cardiovascular damage in workers exposed to EMF. The debate increased in 1974 w hen

the New York Public Service Commission began hearings on a proposed 765 kilovolt

(kV) transmission line. This debate resulted in the funding of a 5-year. $5 million FMI

research program by the New York Electrical Utilities.

The Committee's report (1992) acquainted readers with knowledge that:

Electric fields are produced by the voltage applied to a wire and are measured in volts per meter (V/m). Magnetic fields are produced bv the current flowing through a wire and are measured in terms of gauss (G). The amount of power that a line transmits is the product of its voltage and current. Power systems are designed to hold voltages relatively constant, while currents increase and decrease depending on the power demand. Therefore, for a given voltage the electric field will remain relativelv constant over time, but the magnetic field will increase or decrease depending on power demand, (p. l-l)

There are basically three stages in generating electricity and moving the electricitv

from the electric station to the end user. First, electricity is generated at an electrical

generating station at about 20,000 volts (20 kV). The power is then passed through a

transformer which increases the voltage so that the power can be transported w ith

minimal losses. In the second stage, electricity is transported ov er high voltage

17

transmission lines (i.e.. 69 to 765kV). Transmission lines connect to substations where

the Voltage is reduced and power is transferred to lower-voltage distribution lines. In the

third stage, distribution lines deliver power locally to individual users (PUC. 1992).

In the report the Committee stated that "Electric and magnetic fields are not something

new. Scientists have had a good understanding of them since the nineteenth centurv. For

example, processes in the earth's core give rise to the earth's magnetic field. Unlike the

altemating fields associated with transmission lines and appliances, the earth's magnetic

field does not altemate. but is static" (pp. 1-2).

Electric fields can be easily blocked by trees, buildings, earth and other objects.

However, magnetic fields are not easily blocked and can pass through buildings, earth,

and humans.

The EMF from poweriines and appliances are of extremelv low energv and frequencv.

They are appreciably different in frequency (i.e., Hz) from ionizing radiation (e.g..

gamma rays, x-rays, ultaviolet rays) in the electomagnetic energy spectmm. The energy

in the 60-Hz frequency is not great enough to cause ionization, or ev en great enough to

heat tissue as is the case for microwaves. The non-ionizing and non-heating

characteristics of EMF produced from 60-Hz frequencies are two of the reasons why

some scienfists believe that these fields could not bring about biological changes.

Hovvev er. biological changes hav e been observed, under experimental exposure

conditions, and these observations have increased the concem for possible human health

effects (PUC. 1992).

18

The Committee in their report (1992) also stated that:

Some individuals have presented the contention that EMF exposure to electrical appliances is just as great a potential health hazard as exposure to EMF produced from transmission lines. Because the intensity of EMI decreases rapidly as one moves away from a source, the fields at the edge of the rights-of-way for a transmission line (since the source is 25 feet to 40 feet above the ground) may not be much greater, and in certain cases may be less than, the fields next to an electrical appliance (e.g., oven, hair dryer, electrical shaver, can opener), especially for magnetic fields. Such comparisons are of value, but field intensity is only one of the important variables to be considered in evaluating potential health effects. Exposure duration (i.e., acute vs. chronic) must also be considered. Since most appliances are used infrequently and for short duration, their exposure ma> be of less importance. Also, it is realized that the public perceives involuntary exposure (e.g., transmission lines) to be more of a health hazard than voluntary exposure (e.g., appliances), (pp. 1-3)

Since the late 1970's, extensive research programs evaluating the possible health

effects of exposure to EMF have been performed in the United States. The U.S.

Department of Energy (DOE) and the Electric Power Research Institute (EPRI) have

sponsored much of this research. These studies have helped answer many unknowns, but

many questions remain. On account of these unknowns in the scientific data base, public,

regulatory, and judicial involvements have been initiated (PUC, 1992).

Kaiser (1996) reported that:

To address burgeoning public fears and help decide whether protectiv e regulations were in order, the DOE in 1993. at Congress' request, commissioned the National Research Council (NRC) to detemiine whether EMFs from power lines or household appliances pose a threat to human health. After an exhausfive, 3-year study, a l6-member panel said there is "no conclusive and consistent evidence" that ordinary exposure to EMFs causes cancer, neurobehavioral problems, or reproductiv e and developmental disorders.

After reviewing more than 500 studies, the panel concurred that at v er> high doses, EMFs can have biological effects. These include disruption of

19

chemical signaling between cells in cultures, and inhibifion of melatonin production and promotion of bone healing in animals. But the panel found no adverse effects on cells or animals at the low levels measured in residences.

The committee also found epidemiological studies linking ordinarv EMF exposure to adult cancer and other health problems unpersuasiv e "in the aggregate." Overall, the report concludes, "The current body of evidence does not show that exposure to these fields presents a human health hazard."

But even this string of studies may not lay the controversev to rest. As Dimitrios Trichopoulos, chair of epidemiology at the Harvard School of Public Health, points out, "It's one thing to say, 'Not guilty,' and another to say, 'Innocent.'" For that reason, he predicts, the issue of residential EMFs "will never go away." (p. 910)

Open Space/Parks

According to the 1986 City of Lubbock Comprehensive Land Use Plan, an important

part of community facility planning is the development of parks, open space, and

recreational centers. For efficient and functional development, recreational facilities are

designed to meet the specific needs of the user groups, the demographics of the area, and

adjacent land uses. Associated urban design goals are to create a positive urban image,

while preserving resources which reflect Lubbock's history, heritage, and progress!ve

pride; consider urban design as an important factor in planning for future dev elopment

and growth within the city; ensure that land uses reflect quality use dev elopment and

positive urban image.

Strategies to accomplish the Land Use Plan are to pursue the acquisition of land,

buildings, and endowments to enhance the quality of existing and proposed park and

recreation facilities; to continue the policy of utilizing natural drainage areas as park sites

20

and to beautify and develop Lubbock's open space resources to help create a unique

image.

Conceming public facilities, the Land Use Plan states that, generallv. each square mile

of residential development should include one neighborhood park site; and playas, or drv

lakes, should be viewed as a source for aesthetic amenity, whether privatelv or publiclv

maintained.

21

CHAPTER III

METHODOLOGY

The determination of water surface elevations in playa basins was accomplished,

based on the 100-year, 24-hour storm event, by performing calculations and h> drologic

analyses for each playa watershed within the approximately 9,472 acre study site. 1 he

hydrologic analyses and calculations are procedures developed by the Natural Resources

Conservation Service (NRCS, formerly the Soil Conservation Service). Engineering

Division, to calculate storm mnoff volume, peak rates of discharge, and storage volumes

required for stormwater detention reservoirs. These procedures, published in NRCS

Technical Release 55, Urban Hydrology for Small Watersheds, 2nd Edition, are

applicable in small watersheds, especially urbanizing watersheds. The Technical Release

provides for hydrologic analysis of a watershed under various combinations of land uses

using single-event rainfall data.

Soils play a major role in defining the runoff potential in any drainage basin. Ihe

NRCS has mapped the soils in Lubbock County into four hydrologic soil groups (HSG's)

and classified the mnoff characteristics of each group (A,B.C, and D) according to their

minimum infiltration rate, which is obtained for bare soil after prolonged wetting.

Characterisfics of each of the HSG's are;

Group A; Soils having low runoff potential and high infiltration rates ev en when

thoroughly wetted. They consist chiefly of deep, well to excessively drained

22

sands or gravels and have a high rate of water transmission (greater than

0.30 in./hr.). There are no Group A soils in the study area.

Group B: Soils having moderate infiltration rates when thoroughlv wetted and

consist chiefly of moderately deep to deep, moderatelv well to well drained

soils with moderately fine to moderately coarse textures. These soils ha\ e a

moderate rate of water transmission (0.15-0.30 in./hr.). There are

approximately 6,331 acres of Group B soils in the study area.

Group C; Soils having low infiltration rates when thoroughly wetted and consist

chiefly of soils with a layer that impedes downward movement of water and

soils with moderately fine to fine texture. These soils have a low rate of

water transmission (0.05-0.15 in./hr.). There are approximately 1.267 acres

of Group C soils in the study area.

Group D; Soils having high mnoff potential. They have very low infiltration rates

when thoroughly wetted and consist chiefly of clay soils with a high

swelling potential, soils with a permanent high water table, soils w ith a

claypan or clay layer at or near the surface, and shallow soils over nearlv

impervious material. These soils have a very low rate of water transmission

(0-0.05 in./hr.). There are approximately 640 acres of Group D soils in the

study area.

There is a discrepancy of 1,234 acres between the number of acres in the study area

(9,472 ac.) and the total HSG acres calculated for the study area (8.238 ac). This is due

23

to some acres in the study area not being entered into the ARC/INFO data base because

they are in watersheds that drain outside of the study area, such as watershed no. 5.

Rainfall distribufions were designed to contain the intensity of any duration of rainfall

for the frequency of the event chosen. That is, if the 100-year frequency, 24-hour rainfall

is used, the most intense hour will approximate the 100-year, 1-hour rainfall volume (see

map. Figure 1, page 25).

To estimate runoff from storm rainfall, NRCS uses the Runoff Curve Number (CN)

method. Determination of CN depends on the watershed's soil and cover conditions

which are represented as HSG, cover type, treatment, and hydrologic condition.

Hydrologic condifion indicates the effects of cover type and treatment on infiltration and

runoff and is generally estimated from density of plant and residue cover on sample areas.

Good hydrologic condition indicates that the soil usually has a low runoff potential for

that specific hydrologic soil group, cover type, and treatment. Some factors to consider in

estimating the effect of cover on infiltration and mnoff are (a) canopy or densitv of lawns,

crops, or other vegetative areas; (b) amount of year-round cover; (c) amount of grass or

close-seeded legumes in rotations; (d) percent of residue cover; and (e) degree of surface

roughness (Table 1, page 26).

Most urban areas are only partially covered by impervious surfaces. Therefore, the

soil remains an important factor in mnoff estimates. Urbanization has a greater effect on

runoff in watersheds with soils having high infiltrafion rates (sands and gravels) than in

watersheds predominately of silts and clays, which generally have low infiltration rates.

24

c o

T3

•o c rs

J C

4>

B C/3

go

I

k<

D

a:

u z E i a. PS

t5?

CO

25

Table I Runoff Curve Numbers for Urban Areas.

Cover Description Curve Numbers for Hydrologic Soil Group

Cover type and hydrologic condition A B C D

Fully developed urban areas (vegetation established)

Open space (lawns, parks, golf courses, cemeteries.

etc.);

Poor condition (grass cover less than 50%) 68 79 86 89

Fair condition (grass cover 50% to 75%) 49 69 79 84

Good condition (grass cover greater than 75%) 39 61 74 80

Residential areas (1/4 acre, 38% average impervious

area) 61 75 83 87

26

Calculations of mnoff volume were based on the study area being in a fully developed

condition consistent with the City of Lubbock 1986 Comprehensive Land Ise Plan which

projects the majority of land use to be low density residential.

Runoff volumes and 100-year flood elevafions were determined bv following a series

of successive steps;

1. Boundaries of each watershed that drained into the study area were determined using

USGS maps (scale 1:24,000), one-foot contour maps (scale 1:200) and aerial photos

obtained from City of Lubbock engineering staff, and field observations (Figure 2.

page 28);

2. ARC/INFO, a proprietary geographic information system (GIS) computer software

package, was used to digitize each watershed boundary and the location of each soil

mapping unit (from Soil Survey of Lubbock County) within each watershed. Each

watershed was then numbered and the area, calculated in acres, covered bv each soil

type (mapping unit) by ARC/INFO

3. This information was then used to determine hydrologic soil groups (HSGs) w ithin

each watershed and percent cover for each HSG (see example. Table 2. page 29);

4. Runoff volume in acre-feet was then calculated using Worksheet 2 from TR 55 (see

example. Table 3, page 30);

5. The 100-year flood elevation for each playa was established by using a planimeter to

measure coverage in acre-feet for each one-foot contour surrounding each playa lake

bottom (from City of Lubbock contour maps).

27

98th St

114th St.

FM 1585

28

Soil No. and Acres

1 -675.20

5 - 157.56

6 - 148.48

17- 26.39

18- 146.93

19- 62.07

23- 24.53

30 - 450.89

42- 45.33

46 - 4.39

1741.77

Table 2 Soil Types and Coverage

Watershed No. 1 1741.77 acres

3,239 feet - 100-year flood elevation 634 acre-feet

% of Total Acres

38.77

9.05

8.52

1.52

8.44

3.56

1.41

25.89

2.60

.24

100.00

Hvdrologic Soil Group

B

B

B

B

B

B

D

C

D

B

Acres in Studv Area

516.06

30.35

117.66

23.39

109.23

62.07

24.53

320.00

40.33

0.00

1243.62

29

Table 3 Watershed No. 1 Worksheet

Runoff Curve Number and Runoff

Watershed No. 1 Lake no. 93

Area, square miles (Am) - 2.72 sq. mi.

Frequency, year - 100

Rainfall, P (24-hour) - 7 in.

HSG

B

C

D

D

B

Cover Description

Residential

Residential

Open space, poor condition

Open space, good condition


Curve Number

75

83

89

80

61

Area %

65.10

25.89

2.60

1.41

5.00

Product of CN X Area

48.83

21.49

2.31

1.13

3.05

Totals = 100.00

CN (weighted) = total product total area

76.81 =.7681; Use CN = 77 100

76.81

Runoff depth (Q) in inches for selected CN's and 100 yr. rainfall of 7 inches

Runoff depth for curve number of;

40

.84 in.

45

1.24 in.

50

1.68 in.

55

2.12 in.

60

2.60 in.

65

3.10 in.

70

3.62 in.

75

4.15 in.

80

4.69 in.

85

5.25 in.

90

5.82 in.

95

6.41 in.

98

6.76 in.

Runoff Q = 4.37 in.

Runoff volume = Q x Am x 53.33 = 4.37 x 2.72 x 53.33 = 634 acre feet

30

For further hydrologic information conceming the watersheds in the studv area, refer to

the Appendix entitled Watershed Calculations, page 99.

After the 100-year flood elevation was determined for each plava in the studv area,

thirteen separate land-use master plans, corresponding to the thirteen zones within the

study area, were developed to illustrate the relationship between each playa lake and

surrounding land uses.

31

CHAPTER IV

DISCUSSION

Introduction

All of the landscape master plans have eighteen common planning and design

elements:

1. Each plan, except zones 12 and 13, represents approximately 640 acres of land

corresponding to existing grid sectional roads. Zones 12 and 13 represent

approximately 960 acres each.

2. The design priorities are; (a) stormwater management, (b) surface drainage/overflow

routes between playas, (c) setbacks from electrical transmission lines and

electromagnetic fields (EMF), (d) vehicular traffic flow, and (e) open space, parks,

recreation, aesthetics.

3. All contour lines are taken from City of Lubbock contour maps. They are depicted as

presently existing rather than showing potential post-development contours.

4. The slope of each watershed averages approximately one percent. All of the playa

lakes, except one, are non-overflow lakes. Therefore, earth moving and grading would

be required to create playa overflow routes connecting the playas.

5. Street pattern layout is oriented toward enhancing stormwater infiltration and aesthetic

design rather than other relevant issues such as accommodating fire or other

emergency response vehicles. Residential streets would be constructed on the contour

within each watershed, thereby creating concentric circles surrounding each plava

lake. This design would extend the time runoff stays on the watershed, allowing more

32

time for infiltration and removal of solids and pollutants. It would promote more

even distribution of mnoff over the landscape rather than the traditional method of

channelling runoff in order to remove it from the landscape as quicklv as possible.

6. Curb and gutters that serve as boundaries for parks/open space would be slotted so as

to achieve more uniform distribution of mnoff rather than channelization. Streets that

cross playa overflow routes would also have slotted curb and gutter to accommodate

playa overflow and reduce maintenance requirements.

7. Overflow cross-streets would be constmcted on the 100-year flood elevation to

provide a reference point for playa overflow and as a visual indicator of how close

any storm event approaches the 100-year event.

8. Greenbelt / playa overflow routes would be landscaped with trees that are nativ e to the

southem High Plains and trees that have been proven to thrive in this area; and.

planted with bermuda grass so as to reduce the velocity of playa overflow, therebv

increasing infiltration and reducing pollutants.

9. As stated in the Land Use Plan, "The City Council has determined that it would be in

the best interest of the cifizens of the City of Lubbock to require that residences or

other facilities not be constmcted below the high water level of Playa Lakes within

the City of Lubbock;..." With this in mind, development is planned to take place

beginning at least one foot, and in most situations two to three feet above the 100-year

flood elevation.

10. A school is located in each section plan except zone 9 where approximately 75% of

the area is occupied by existing land uses. Locating a school in each zone, and

adjacent to park facilifies, is consistent with the City of Lubbock Comprehensive

33

Land Use Plan which states that "generally, each square mile of residential

development should include one elementary school and one neighborhood park site".

11. Regarding commercial development, "a maximum of 10 acres of commercial zoning

should be allowed on each comer at the intersection of major thoroughfares, serv ing

neighborhoods within Vz to I mile radius". A 10-acre commercial comer was shown

on most plans except where the comer existed in a low-lying, flood-prone area.

12. Another strategy of the City of Lubbock is "to instill a sense of neighborhood

identity...", and to "foster an environment which creates and maintains identifiable,

viable, and quality residential neighborhoods and promotes communitv spirit".

Newly developed neighborhoods could gain their identity from the playa lake and

open space system each is centered around, with neighborhood associations creating

an awareness of the hydrology and ecology of "their" playa.

13. To deal with the high-voltage electrical transmission lines running east and west

through the middle of the upper half of the study area, a linear park is designed to

buffer surrounding development from the lines and electric utility easement. The

linear park can be a component of the strategy of Lubbock 2005 Goals to "beautify

and develop Lubbock's open space resources to help create a unique image". In

several instances, the linear park intersects or is otherwise connected to playa

greenbelt/overflow routes in order to create a continuous open space and recreational

"path" from the west end of the study area to the east end. The linear park and

connecting playa greenbelts could be promoted as sites to attract schools and other

organizations in the region for cross-country track meets or other activ ities which

could induce participants from out of town to patronize local hotels and restaurants.

34

etc. Open space within the linear park could also foster neighborhood identitv bv

being used for neighborhood garden plots.

14. Each open space / stormwater park can be developed as needed with ball fields and

courts, playground equipment, community centers, etc. to satisfy the recreational

needs of adjacent neighborhoods.

15. Collector streets are designed to intersect major thoroughfares approximatelv half

way between section roads to be consistent with existing City of Lubbock

street layout. Collector streets that border playa lakes are designed to serve as park

boundaries, and with their slotted curbs and gutters to distribute runoff evenlv as it

enters each playa basin.

16. The electrical utility easement/linear park is designed with widths varving from 80

feet to 300 feet. The purpose of the varying width is to offset and soften the rigid

lines formed by the transmission lines and towers, while providing more v isual

interest. Trees would be planted randomly in varying width pattems along the park

boundaries to create a more natural feel while providing a visual as well as an actual

buffer separating the transmission lines from adjacent residential areas.

17. Generally, parking areas are located in parks in proximity to intersections for ease of

access and egress to and from outlying areas.

18. In all of the zones there are existing uses, such as residenfial units (houses). Within

each zone, if the area occupied by existing uses is insignificant and does not affect the

proposed land use plan concept, the existing uses are shown to be zero on the land use

table accompanying each site plan discussion.

35

Individual Site Plan Discussion

Zone I. Figure 3. page 39

This plan represents the far northwest comer of the study area. Its boundaries are

98th Street on the north, 114th Street on the south, Milwaukee Avenue on the east, and

Upland Avenue on the west. Ninety-eighth Street splits lake #94 (lake numbers

correspond to City of Lubbock numbering system) in the northeast comer of Zone 1.

This playa lake receives mnoff (481 acre feet in a 100-year event) from one of the largest

watersheds affecting the study area. This watershed (watershed #2) consists of

approximately 1,263 acres and at its most distant point extends more than Vi mile north of

the study area. The 100-year flood elevation (the term "flood elevation" or "flood level"

in successive descriptions means the 100-year flood elevation, unless otherwise stated)

for lake #94 was calculated to be 3,261 feet.

Watershed #7 drains into lake #94-B and consists of approximately 385 acres, the vast

majority being contained within zone 1. The volume of mnoff received by lake #94-B

due to a 100-year storm is 136 acre-feet, which would place the water level at an

elevation of 3,275 feet.

The 100-year flood and constructed overflow elevation of lake #94-B is 14 feet above

the 100-year flood elevation of lake #94, thereby creating a northerly overflow path. This

contradicts the normal direction of the slope of the land which is to the southeast. The

flood level of lake #94-B is also 2 feet higher than that of lake #182 which is south of

lake #94-B in zone 2. Therefore, it is conceivable that in the event of a storm greater than

a 100-year event, lake #94-B could also flow south of 114th St. into lake #182 in zone 2.

36

A lO-acre commercial area is shown in the northeast comer of the section, well inside

of the 100-year flood elevation. No development should be attempted in this comer

without extensive earthwork (fill) being done to raise the floor elevation of the site above

the flood elevation. Therefore, it may be desirable to leave this comer as open space.

In the southeast comer of the plan are existing "high-end" horse stables totaling

approximately 40 acres (6% of zone I). Separate horseback riding trails could be

incorporated into the recreational plan for the open space/park areas.

The combined area covered by the playa basin park and greenbelt is approximatelv

140 acres, or 22% of zone 1. The linear park shown mnning in an east/west direction

consists of approximately 22 acres, or slightly more than 3% of zone I. varying in width

from 80 feet to 300 feet. This park effectively divides zone I in half, with the greenbelt

and playa park further dividing the zone so that four separate residential areas are created

totaling approximately 398 acres, or 63% of zone I.

The collector streets mn basically north/south and east/west. However. streets are

placed proximal to contours where possible to facilitate desirable drainage direction.

There are four residential areas separated from each other bv a park or greenbelt. This

open space separation could be a potential benefit to developers by allowing each area to

have its own architectural style, residential price range, and sense of neighborhood.

Residential area number 1 is divided diagonally by watersheds #2 and #7, and is

separated from adjacent residential areas by the linear park on the south, a greenbelt on

the east, and major thoroughfares on the north and west.

37

Residential area number 2 is bounded on the north by the linear park, major

thoroughfares on the south and west, and separated from area number 4 to the east by an

expanse of open space created by playa lake #94-B.

Residential area number 3 is totally enclosed by parks and open space except for a 400

foot frontage on the east side with Milwaukee Ave. This enclosed area could be planned

as a very desirable area for residential lots with corresponding higher prices for those lots.

Residential area number 4 is enclosed by the linear park on the north, lake #94-8 w ith

its corresponding open space on the west, major thoroughfares on the south and east, and

the horse stables and commercial zone in the southeast comer. A developer(s) mav want

to plan for a barrier or screen to separate residences from adjacent horse stables and

associated nuisances. One of the associated "nuisances", ie. horse manure, could ev en be

a valuable resource for gardeners in the area.

A school is located in the northeast quadrant within the park boundary approximately

one foot above the flood elevation, and approximately 700 feet from the electrical

transmission lines.

38

c CO

^ 0 c

0 U g u q w q M

0 <

3

>

L

-t-

3 E O

•A-

u

-^ ^ 5 N -+- U -+- U U =5 -r I, c o a en

I- 0

u - C O IP « **

c o

60 CL,

c 0 •:=•

L B / -

| .

, , , . . ]

o

t-

in

»0

•I' c^V/.

1 < r.

(0

" ~i * 4

o

OD

VO

• *

S 1 c 1

SMu;?:"

•a/^t> 7) o"^ n c m 1 iiu

Table 4 Proposed Land Uses

Zone 1 630 acres

Open Space Commercial Residential Existing Uses

No. Acres 162 30 398 40

% of Total 25.7 4.7 63.2 6.4

40

Zone 2. Figure 4. page 43

The boundaries of the zone represented in Figure 4 are 114th Street on the north, FM

1585 on the south, Milwaukee Avenue on the east, and Upland Avenue on the west.

Most of watershed #13, containing approximately 444 acres, drains into lake #182. which

would receive approximately 157 acre-feet of mnoff during a 100-year storm. The

overflow from lake #182 would travel south/southwest to lake #185 which is south of FM

1585, outside of the study area. The combined area of the playa park and connecting

greenbelts is approximately 90 acres, or 14% of zone 2. This site presents no unusual

problems for development other than the grading required to create an overflow path.

This zone should be desirable for development because the majority (approximatelv 510

ac, or 80%)) of the zone is suitable for residential development. Each of four residential

areas borders the playa basin to greater or lesser extent.

The collector streets run, basically, in a north-south and east-west pattem, except when

circumscribing the playa park. They separate zone 2 into four residential areas.

Residential area number 1 is affected by three different watersheds - #7. #13. and the

eastern edge of an unnumbered watershed that drains westward out of the studv area. The

unnumbered watershed (and subsequent unnumbered watersheds) was excluded from

being numbered because it drains into a playa outside of the study area. This residential

area is bounded on the north and west sides by major thoroughfares, on the east side bv a

greenbelt, and on the south side by a park and greenbelt.

Residential area number 2 borders major thoroughfares on the south and west sides,

and greenbelts on the east side and north side connected by a sweep of park border. The

41

border separating residenfial area number 2 from lake #182 is the longest of all the

residential areas in this zone. Therefore, numerous residences could hav e uninterrupted

V istas to the lake and beyond.

Residential area number 3 is bordered on the north and east bv major thoroughfares, a

greenbelt on the west side, and by residential area number 4 on the south. There is some

existing residential use in the form of manufactured housing located in the area where the

school is proposed. This area is very flat with a slope of less than 1%, thereby allowing

more time for infiltration of precipitation.

Residential area number 4, also, should be relatively easy to dev elop because the land

does not slope very much. Its boundaries are residential area number 3 on the north,

major thoroughfares on the east and south, and the playa park and a greenbelt on the west.

There are a few scattered residences in this area that it is assumed will be replaced b> new

development.

The proposed site for the school is approximately 5,100 feet from the electrical

transmission line in zone 1 (page 39).

42


Zone 2 640 acres


No. Acres 90 40 510 0

% of Total 14 6.25 79.75 0

44


The boundaries of the zone shown in Figure 5 are 98th Street on the north. 114th

Street on the south, Frankford Avenue on the east, and Milwaukee Avenue on the west.

In the northwest comer is the continuation of lake #94. The intersection of 98th Street

and Milwaukee Avenue would need to be built up to prevent it from being cov ered bv

water during heavy storms so that vehicular traffic would not be dismpted. At this time

there is no development in this zone. The land is used primarily for pasture, being

covered with grasses with sporadic areas of mesquite and Siberian elm. Lake #^4 is a

non-overflow lake and, therefore, extensive earthmoving would be required to create a

path for overflow to be routed to lake #132, southeast of lake #94. This would confront

another factor, that being the 100-year flood elevation of lake #132 being 3,266 feet, 5

feet above the 3,261 feet flood elevation of lake #94. However, there are two potential

outlets from lake #132: one that goes east-northeast to lake #93 (zone 5) with a flood

elevation of 3,239 feet, and a second that travels southeast to lake #200 (zone 4) hav ing a

flood elevation of 3,260 feet. It should be remembered that the greenbelts / playa

overflow routes will also provide storage capacity and infiltration for runoff The

combined areas of the playa parks and greenbelts are approximately 100 acres, or 18% of

zone 3.

45

The collector streets mn, essentially, north-south and east-west intersecting in the

middle of the zone. This zone is more complex to develop because of the plava overflow

characteristics described in the previous paragraph which result in six separate residential

areas totaling approximately 412 acres (74% of zone 3).

Residential area number 1 is one of the more steeply sloped areas in the studv area

with a slope of approximately 3% from the highest point to the park boundary. This

should not pose any problems for development, but is a somewhat unusual feature for the

study area.

Vegetative filter strips should be constmcted on the south side of the commercial area

proposed in the northwest comer of this area to trap pollutants carried by runoff from

paved areas because of the close proximity of lake #94. It is assumed that vacant vehicle

parking areas in the commercial area could be utilized by visitors to the adjacent park.

Residential area number 2 is another of those areas that is almost total Iv enclosed bv

parks and greenbelt. Approximately 450 feet on the eastem side borders a collector

street. This area could also enclose higher priced residential lots in close proximitv to an

elementary school and proportionately large park/open space frontage. The proposed

school is approximately 400 feet from the electrical transmission lines.

46

The boundaries of residential area number 3 are a greenbelt on the north side, major

thoroughfares on the west and south sides, and playa lake #132 on the east. Its border

along the park boundary is the longest of any of the residential areas in this zone.

Major thoroughfares enclose residential area number 4 on the north and east sides, the

linear park bounds the south side, and a collector street is the west side boundarv. It is a

relatively flat area suitable for development.

Residential area number 5 is bordered by the linear park on the north, a greenbelt on

the south, a collector street on the west, and approximately 300 feet of major

thoroughfare frontage on the east side.

Residential area number 6 has boundaries of major thoroughfares on the east and south

sides, a greenbelt on the north side, and a park on the west side.

The linear park running east and west through the middle of this zone is composed of

approximately 28 acres, or 5% of zone 3.

47

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Zone 3 560 acres


No. Acres 128 20 412 0

% of Total 22.8 3.6 73.6 0

49


The 640 acre zone illustrated in Figure 6 is bounded on the north by 114th Street. IM

1585 on the south, Frankford Avenue on the east, and Milwaukee Avenue on the west.

Playa lake #200, situated in the southeastem comer of the section, would receiv e runoff

from lake #132 in zone 3. The flood elevafion of lake #200 is 3,260 feet receiving 148

acre-feet of runoff in a 100-year storm event. Lake #200 extends across Frankford

Avenue into zone 6. The biggest challenge is planning the overflow route around or

through the existing residential area in the northeast comer of the zone. The playa park

and greenbelt system take up approximately 68 acres, or 11% of zone 4.

The collector streets run generally north-south and east-west, and also act as a

boundary for the playa park. They separate zone 4 into four residential areas totaling

approximately 500 acres (78%)).

Residential area number 1 is bounded on the north and west by major thoroughfares,

and on the east and south by collector streets.

Residential area number 2 has major thoroughfares as boundaries on the west and

south, and collector streets for the north and east boundaries. The juncture of three

watersheds (#16, #14, and #9) meet in the southeast part of this residential area.

50

Residential area number 3 is crossed by the playa overflow route connecting lake #132

in zone 3 to lake #200. This residential area is bounded by major thoroughfares on the

north and east, and collector streets on the west and south. There are approximatelv 42

acres of existing residential development beginning in the northeast comer of this area

and extending westward approximately V2 mile. The greenbelt weaves among

undeveloped areas of this development. There is also commercial development in the

form of a retail nursery facing Frankford Avenue.

Residential area number 4 has collector streets for boundaries on the north and west

sides, FM 1585 on the south, and the playa park on the east side. A school is located

within the park boundary in this area, approximately 5,500 feet from the electrical

transmission lines north of this zone in zone 3 (page 48). Frankford Avenue would need

to be built up in the area of lake #200 to avoid being covered with water due to heav v

rainfall.

51

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Zone 4 640 acres

Commercial

30

4.7

Residential

500

78

Existing Uses

42

6.6

53


The boundaries of this zone are 98th Street on the north, 114th Street on the south.

Slide Road on the east, and Frankford Avenue on the west. Watershed #1. the largest

watershed in the study area enclosing approximately 1,742 acres, drains into lake #93, the

largest playa in the study area with a 100-year mnoff capacity of approximately 634 acre-

feet, which would limit the area that could safely be developed. Lubbock city limits

extend 660 feet south from 98th Street into this section. Overflow from lake #132 in

zone 3 could drain into lake #93 through a graded drainage swale, as well as runoff

originating from the north outside of the study area. The overflow outlet for lake #93 is

almost in the middle of the zone along Slide Road. Overflow would cross Slide Road

then flow north adjacent to Slide Road. The commercial land use proposed in the

northeast comer would need to be built up to elevate it above the flood elevation.

Therefore, it may be desirable to leave this comer as open space. Open space and

greenbelt areas take up approximately 155 acres, or 28% of zone 5. There are no other

watersheds that affect this zone.

The linear park mns east and west and extends in and through the playa park. The

area of the linear park outside of the playa park and not combined with the greenbelt is


The layout of the collector streets is influenced, if not dictated, bv the large plava park.

The street beginning at 98th Street in the middle of the zone heads south , then curves

around the stormwater park on the contour, and ends on the east side at Slide Road. The

54

collector street beginning at Frankford Avenue and heading east is enclosed bv the linear

park on the north side, and by the greenbelt on the south side. In approximatelv the

middle of the zone the greenbelt and linear park meet and combine, continuing eastward

together into the playa park. Where the linear park and greenbelt meet there is a collector

street from the south which intersects the collector street which runs parallel to the linear

park and greenbelt. These collector streets divide zone 5 into three residential areas

totaling approximately 372 acres (66% of zone 5).

Residential area number 1 is bounded by 98th Street on the north, Frankford Avenue

on the west, the stormwater park on the east, and the linear park on the south. This area

slopes approximately 2% from the northwest contour to the park boundarv.

Residential area number 2 is enclosed by the greenbelt on the north, a collector street

on the east, and major thoroughfares on the west and south.

Residential area number 3 has extensive park frontage along the north side, a collector

street on the west side, 114th Street on the south side, and Slide Road on the east side.

A school is proposed on the north side of the zone within the playa park outside of the

flood elevation. Since the school is located in close proximity to lake #93. biology and

environmental studies classes could be conducted outside of the classroom. The

proposed school is located approximately 2,500 feet from the electrical transmission

imes.

55

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Zone 5 560 acres


No. Acres 168 20 372 0

% of Total 30 3.6 66.4 0

57


The proposed land uses represented within zone 6 are bounded on the north bv 114th

Street, FM 1585 on the south. Slide Road on the east, and Frankford Avenue on the west.

Lake #200 with a flood elevation of 3,260 feet extends into the southwest portion of this

zone from zone 4. The outer edge of lake #189 with a flood level of 3.240 feet is in the

extreme southeast comer of this zone. This open space in the southeast comer is part of a

much larger playa that is outside of the study area. The greenbelt connecting the two

playas parallels FM 1585. The playa parks and greenbelt take up an area totaling

approximately 60 acres, or slightly more than 9% of zone 6.

The north-south collector street layout attempts to approximate the contour of the land,

while the east-west streets are offset as they intersect with the north-south street. This

collector street layout divides zone 6 into four separate residential areas totaling 550 acres

(86%) including existing residential uses.

Residential area number I is bordered on the north by 114th Street. Frankford .Avenue

on the west, and collector streets on the south and east sides.

Residential area number 2 is bordered by collector streets on the north and east sides, a

greenbelt on the south side, and a plav a park on the west side.

58

Residential area number 3 has major thoroughfares for boundaries on the north and

east sides, and collector streets on the south and west sides. Included in the lower part of

this area is an approximately 74 acre development of single-family residences.

Residential area number 4 is bordered by collector streets on the north and west sides,

a greenbelt on the south side, and Slide Road and playa park on the east side. There is a

residence and small business in the southeast comer of this area which will probablv

experience flooding problems when/if this area is developed (or even now if a significant

rain event occurs).

There are other commercial uses, permanent residences, and manufactured housing

(mobile homes) sparsely mixed with the predominant agricultural use of the land in this

zone. None of these other existing uses significantly affect the proposed landscape plan.

A school is proposed in the middle of this zone adjacent to the intersection of two

collector streets.

59

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Zone 6 640 acres

Open Space Commercial Residential Other Exisfing & Proposed Existing Uses

No. Acres

% of Total

60

9.4

30

4.7

550

85.9

0

0

61


The boundaries of zone 7 are 98th Street on the north, 114th Street on the south.

Quaker Avenue on the east, and Slide Road on the west. The City of Lubbock extends

660 feet into this section from 98th Street. This was one of the more challenging zones to

plan and design the overflow route because of the natural inclination to move stormwater

the shortest distance, southeast from lake #93 in zone 5 to the closest playa in zone 7,

lake #90-D. However, to do this would require extensive earth moving to negotiate a

positive elevation change of approximately 20 feet separating the two playas. Also, the

flood elevation of lake #90-D at 3,245 feet is six feet higher than that of lake #93. Lake

#90-D receives runoff from watershed #10 and overflows into a greenbelt that carries the

overflow to lake #90-C in zone 10. A more subtle route to the north and east to lake

#90-A in zone 9, which has a flood elevation of 3,218 feet, was determined to be less of

an assault on the landscape. Also, existing land uses along Slide Road in the form of a

golf facility, a church, and a retail nursery were factors that affected this proposed design.

The playa overflow route and playa park take up an area of approximately 109 acres, or

19% of zone 7. The commercial area proposed in the southeast corner of the zone would

need to be built up to an elevation above the flood level of 3,245 feet, or a more desirable

land use may be to leave this comer as open space.

62

The linear park mns west to east with an area of approximately 32 acres, or 6% of this

zone. At the west end of the proposed linear park there is an existing residence located

approximately where the proposed parking area is shown that it is assumed would be

condemned to make room for the linear park.

The collector streets run north-south and east-west, and around the plava park. Thev.

and the parks and greenbelt, help define four separate residential areas totaling

approximately 319 acres (57%).

Residential area number 1 is bordered by the greenbelt on the north and west sides, a

collector street on the east side, and the linear park on the south side. The greenbelt on

the west side would provide an attractive buffer from the heavy vehicular traffic on Slide

Road. There is an existing church with property consisting of approximately 10 acres in

the southwestem comer of this zone.

The borders of residential area number 2 are a collector street and linear park on the

north, a collector street on the east, the playa park on the south, and existing commercial

uses on the west side. The exisfing commercial uses consist of an approximatelv 45'/2

acre golf facility, a 20 acre retail nursery, and a 5 acre area of self-storage mini-

warehouses. This residential area is irregularly shaped which may make it more difficult

63

for developers to design residential street and lot layouts. It may be more suitable for

medium to high-density residential use rather than low-density residential.

Residential area number 3 has borders consisting of the greenbelt on the north. Quaker

Avenue on the east, the linear park on the south, and a collector street on the west.

Existing commercial use is in the northeast comer in the form of a retail nurserv on

approximately 7 acres. There is also an approximately 2 acre electrical sub-station in the

southeastem comer.

The boundaries of residential area number 4 are a collector street and linear park on

the north, Quaker Avenue on the east, the playa park on the south, and a collector street

on the west.

A school is proposed within the boundaries of the playa park approximatelv 1.600 feet

from the electrical transmission lines.

64

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Zone 7 560 acres

Open Space Commercial Residential Existing Ises

No. Acres 141 15 319 85

% of Total 25.1 2.7 57 15.2

66


The zone shown in this figure has boundaries of 114th Street on the north. FM 1585

on the south, Quaker Avenue on the east, and Slide Road on the west. There is scattered

existing residential use throughout this zone that is not shown because it does not

significantly affect this proposed plan. Lake #189 in the southwest corner, w ith a Hood

elevation of 3,240 feet, is an extension of a larger playa located outside of the study area.

This is similar to lake #90-D in zone 7 which extends south across 114th Street into this

zone. The elevation of 114th Street, which divides lake #90-D, would need to be raised

above the flood elevation so that vehicular traffic flow would not be interrupted in the

event of heavy rainfall. It (114th Street) would have slotted curbs and gutters as it crosses

lake #90-D so that overflow could move unimpeded toward lake #90-C (Figure 12. p.77).

The total area covered by the playa parks and greenbelt is approximately 73 acres

(slightly more than 11% of zone 8).

The collector streets run basically north-south and east-west. The street that intersects

Slide Road on the west side of the zone is offset from the middle so that it meets the

adjacent street in zone 6. The collector streets separate this zone into four separate

residential areas totaling approximately 537 acres (84% of the zone).

67

Residential area number 1 is bounded on the north bv 114th Street and the plava park.

collector streets on the east and south, and Slide Road on the west. Stormwater runotT

flows northeast to the playa park and lake #90-D.

Residential area number 2 has collector streets for boundaries on the north and east

sides, and major thoroughfares and a stormwater park on the south and west sides. The

majority of stormwater runoff from this area flows into lake #189 in the southwest corner

of this area.

Residential area number 3 is bounded on the north by 114th Street and the plava park,

Quaker Avenue on the east, and collector streets on the south and west sides. The

greenbelt connecting lake #90-D to lake #90-C in zone 10 winds through the northeast

part of this area.

Residential area number 4 has boundaries of collector streets on the north and west

sides, and major thoroughfares on the east and south sides.

A school is proposed near the middle of the zone adjacent to the intersection of the

collector streets.

68

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No. Acres

% of Total

Open Space

73

11.4


Zone 8 640 acres

Commercial

30

4.7

Residential

537

83.9

Existing I

0

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70

Zone 9. Fiizure IE page 73

This zone is bounded by 98th Street on the north, 114th Street on the south.

Indiana Avenue on the east, and Quaker Avenue on the west. The Citv of Lubbock,

comprising more than half of this section, and the exisfing land uses leave only

approximately 160 acres in the southwest quadrant to be planned. Lake #90-A w ith a

flood elevafion of 3,218 feet, located in the existing Pine Valley Golf Course, is the

desfinafion for overflow from lake #93 west of Slide Road in zone 5 (Figure 7.

p. 65). Overflow from a playa lake northwest of, and outside of the study area, is

depicted by dashed lines. This overflow route intersects with the greenbelt

approximately in the middle of zone 9.

The city limits of Lubbock run parallel to, and north of, the electrical transmission

line. Therefore, the plan proposal for the linear park is confined to the area south of

the transmission line. The proposed linear park occupies approximatelv 8 acres, or

3%, of zone 9. The greenbelt covers an area of approximately 7 acres (2'/2% of zone

9). The greenbelt and linear park combine together from Quaker Avenue eastward

for approximately 2,200 feet. From that point the greenbelt bends southward as it

meanders toward lake #90-A.

71

There are two single-family residences in the northeast comer bordering the

transmission line easement which prevent the linear park from extending farther east

in this zone. The single collector street extends from Quaker Av enue eastward and

parallel with the greenbelt for approximately 1,400 feet before it curves to the

northeast to intersect the Lubbock city limit line joining an existing city street. The

proposed residential area consists of approximately 135 acres which is approximatelv

49% of zone 9.

The existing 53 acre residential subdivision and 65 acre golf course that are

outside the city limits combine to occupy approximately 118 acres (42%) of the studv

area within this zone. The subdivision and golf course extend eastward to Indiana

Avenue.

A school is not proposed in this area because it is assumed there will be one

inside the Lubbock city limits of zone 9.

72

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Zone 9 278 acres

Open Space Commercial Residential Existing I'ses

No. Acres 15 10 135 118

% of Total 5.4 3.6 48.6 42.4

74


The boundaries of this secfion are 114th Street on the north, FM 1585 on the south.

Indiana Avenue on the east, and Quaker Avenue on the west. Lake #90-C is a true

overflow lake, overflowing at an elevation of 3,226 feet, and flowing northeast into lake

#90-A with a flood elevafion of 3,218 feet. The area covered by the two plava parks is

approximately 100 acres, or slightly less than 16% of zone 10. Overflow from lake

#90-A runs southeast through a graded drainage swale to lake #90-B in zone 11 (Figure

13, p. 71). The proposed greenbelts occupy a total area of approximatel) 20 acres

(slightly more than 3%).

The collector streets basically mn north-south and east-west. Together w ith the

greenbelt they divide zone 10 into five separate residential areas totaling approximatelv

480 acres (75%).

Residential area number 1 has major thoroughfares on the north and west sides, a

collector street on the east, and the playa park on the south side.

Residential area number 2 is bordered by the playa park on the north, collector streets

on the east and south sides, and Quaker Avenue on the west. The playa park dominates

both area number 1 and area number 2.

Residential area number 3 has collector streets for boundaries on the north and east

sides, and major thoroughfares on the south and west sides

75

Residential area number 4 is bounded on the north by the plava park. Indiana Av enue

on the east, and collector streets on the south and west.

Residential area number 5 is bordered by major thoroughfares on the east and south

sides, and collector streets on the north and west sides. This area is v er\' flat with the land

sloping less than Yi of 1% from the southwest comer to the northeast comer.

A school is proposed near the intersection of 114th Street and the collector street

approximately 2.700 feet from the electrical transmission line in zone 9 (Figure 11.

p. 73).

The Citv of Lubbock occupies approximately 10 acres of the proposed commercial use

in the northeast comer of this zone within the flood level of lake #90-A. It may be more

desirable to leave the northeast comer as open space rather than raising the elev ation

above the flood level.

76

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Zone 10 630 acres

Open Space Commercial Residential Existing I 'ses

No. Acres 120 30 480 0

% of Total 19 4.8 76.2 0

78


This zone has boundaries of 114th Street on the north, FM 1585 on the south.

University Avenue on the east, and Indiana Avenue on the west. There is a large

playa lake, #90-B, as well as existing land uses, and the City of Lubbock extends

660 feet south from 114th Street into this section. There are approximately 10

acres of existing commercial development and approximately 10 acres of church

property in the northwest comer of the plan area. The westem portion of lake #208

with a flood elevation of 3,202 feet is in the southeastem part of this zone. The

proposed plan shows lake #90-B with a flood elevation of 3,199 feet overflowing

into lake #208. However, the flood elevation of lake #208 at 3,202 feet is three feet

higher than that of lake #90-8. The overflow ouflet of lake #208 (see zone 13,

Figure 15, p. 73) would need to be constmcted at 3,199 feet for overflow from lake #90-B

to occur. The subsequent overflow from lake #208 would travel southeast outside the

study area to the next closest playa lake with an approximate flood elevation of 3.190 feet

(based on United States Geological Survey map edited in 1985). The playa parks oecupv


The existing commercial land use located in the middle part of the eastem side

80consists of a cattle sales bam, and cattle holding pens which extend westward into the

79

flood level (3.199 feet) of lake #90-B. The cattle pens are a potential source of

contamination of the water in lake #90-B. It is assumed that proposed residential land

uses on the north and south sides of this business along with increased land values

associated with development will encourage the sale bam to relocate allowing residential

uses to take its place. That is the reason a collector street is proposed going through

the cattle holding area of the auction yard. The area inside of the Citv of Lubbock is

basically undeveloped and is presently used as agricultural land.

The playa park located in the middle of this zone requires the collector streets to

circumscribe the boundaries of the park, intersecting at right angles with streets that

connect to the major thoroughfares that bound this zone. Collector streets are show n

extending into the city of Lubbock because the flood elevation of lake #90-8 extends

well into the city limits. The collector streets and greenbelts divide this zone into six

residential areas totaling approximately 340 acres, or 61% of zone 11.

Residential area number 1 is a small area bounded by the Lubbock citv limits on the

north, the church property on the west, the playa park on the east, and a greenbelt on

the south.

80

Residential area number 2 has boundaries of a greenbelt on the north side, the plava

park on the east side, a collector street on the south side, and Indiana .Av enue on the

west side.

Residential area number 3 is bounded by a collector street on the north, the plav a

park and collector streets on the east, FM 1585 on the south, and Indiana Avenue on

the west.

Residential area number 4 has boundaries of the Lubbock citv limits on the north,

the playa park on the west. University Avenue on the east, and the cattle sale^ bam on

the south.

A collector street is the northem boundary for residential area number 5. Universitv

Avenue and a playa park the eastem boundary', a greenbelt is the southem boundarv. and

a collector street the westem boundary.

Residential area number 6 is bounded on the north bv a collector street, a greenbelt

and playa park on the east, FM 1585 on the south, and a collector street on the west.

A school is proposed in the northwest comer of residential area number 6 near the

middle of this zone.

81

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Zone 11 560 acres

Open Space Commercial Residential Existing Ises

No. Acres 146 20 340 54

% of Total 26 3.6 60.7 9.7

83


The zone represented in Figure 14 is in the far northeast comer of the studv area. Its

boundaries are 98th Street on the north, 114th Street on the south. U.S. Highway 87 on

the east, and University Avenue on the west, with Avenue P dividing this area north to

south. The City of Lubbock extends 660 feet each way from the north and west sides into

this zone. The area contained within the Lubbock city limits on the north side of this zone

is undeveloped, vacant land. However, the area on the west side within the citv limits

contains a large percentage of commercial use. Within the master plan area there are

existing commercial and residential land uses that divide this zone so that continuitv of

the landscape plan concept is dismpted. The existing commercial land use on the westem

side of this zone consists of approximately 50 acres of combination office/shop/

warehouse metal buildings. This area extends into the bottom of lake #84-A, and will

probably experience flooding problems when this zone is fully developed. Therefore,

relocating existing commercial land uses to areas outside of the flood level is

recommended. There is also an approximately 11V2 acre commercial area in the

southwestem part of the zone. The existing residential land use in the area bordered by

Avenue P on the east and 114th Street on the south is approximatelv 45'/2 acres of

primarily manufactured housing. The proposed greenbelt shown intersecting the existing

residential area enters a depression that is preserved in its existing state to hold existing

runoff from the mobile home development. The area contained within the proposed plava

park and greenbelts is approximately 91 acres (11% of zone 12).

84

The proposed layout of the collector streets is defined by the playa park and existing

land uses. Two collector streets are shown entering the zone on the west side, one on the

south side of the existing commercial area and the other on the north side of the proposed

linear park. These two streets encircle the playa park and meet. Three other collector

streets intersect the circular street, one each on the north, east, and south sides of the park.

The proposed linear park (comprising approximately 35 acres, or 4°/o) enters zone 12

from the west and continues eastward into and through the playa park until it ends at the

eastem boundary of the studv area, U.S. Highway 87.

The proposed linear park, greenbelts, and collector streets divide zone 12 into five

residential areas totaling approximately 242 acres (30%).

Residential area number 1 is bounded on the north and west sides bv the Lubbock citv

limits, a collector street on the east, and the playa park on the south.

Residential area number 2 is bounded on the north by a collector street and existing

commercial uses, a collector street on the east, 114th Street on the south, and Lubbock

citv limits on the west. Existing commercial use projects from the south into the middle

of this area.

Residenfial area number 3 is bounded on the north by the linear park. Av enue P on the

east, a greenbelt on the south, and the playa park on the west.

Residential area number 4 is a very small area enclosed bv a greenbelt on the north and

east, the playa park on the west, and the existing residential development on the south.

85

Residential area number 5. bounded on the south by 114th Street and a collector street

on the west, would be joined together with residential area number 4 if not for the

existing residential development on the north and east.

The land uses of the area due north and outside of the study area consist of a large

percentage of residences and other buildings of substandard construction. Due to the

dilapidated nature of the area mentioned, it would probablv be difficult to attract

residential development, other than manufactured housing, to the area represented in /one

12. Another factor is that the southeast quarter of the section north of the studv area.

bordered by Avenue P on the east and 98th Street on the south, is an area commonly

known as "horse city" where a large number of horses and livestock are kept. Therefore,

an equestrian park is proposed as a land use in the northeast comer of the section

bordered by 98th Street on the north. Avenue P on the east, the linear park on the south,

and a collector street and playa park on the west.

The open space of an equestrian park would provide a buffer between existing and

proposed land uses south of 98th Street and west of Avenue P. The proposed residential

development of this zone could even be oriented toward horse enthusiasts who would be

allowed to keep a couple of horses per residential lot. This non-confomiing residential

use would be buffered from other residential uses west of this zone by the plava lake and

existing commercial land uses, but be consistent with the non-conforming uses in "horse

city.'" The area between Avenue P and U.S.Highway 87 would also be designated as an

equestrian park due to the substandard conditions of the neighborhood north of this area,

the presence of a large population of horses and horse enthusiasts in the immediate area.

86

the heav^ traffic on Highway 87, and the presence of "the strip" due east across 1 lighway

87, all of which do not make this area desirable for residential development. An

equestrian park could be developed to attract horse enthusiasts from throughout the

region, and beyond, by constmcting facilities to host equine related activ ities such as

horse shows and competitions, educational and training seminars, a polo field for the

Texas Tech polo team, and a horse information center/museum as it relates to the South

Plains. Along Highway 87 commercial development could be established in the form of a

horse motel for travelers hauling horses, and retail businesses oriented toward attracting

horse enthusiasts. The total area comprising the proposed equestrian park is

approximately 300 acres (37% of zone 12).

A school is proposed in the southwestem part of the equestrian park adjacent to the

north/south collector street, the playa park, and greenbelt. The proposed school is

located approximately 900 feet from the electrical transmission lines.

87

18 Ar iL\ / i n

J y

Si.

^

^

-C

^

^ T g o i s -

ôo^"/

'9»/, d •2)A*C


Zone 12 805 acres


No. Acres 426 30 242 107

% of Total 53 3.7 30 13.3

89


The boundaries of this area are 114th Street on the north, FM 1585 on the south. I .S.

Highway 87 on the east, and University Avenue on the west. It is an area div ided by

existing land uses. There is an existing residential development totaling approximatelv

160 acres bordered by Avenue P on the east and FM 1585 on the south. The 10-acre

commercial area in the northwest comer is within the Lubbock city limits. Ihere are

approximately 100 acres of existing commercial use on the west side. This commercial

area extends to the 3,197 feet level of lake #208, well within the 3.202 feet flood level.

The playa park covers approximately 54 acres (SYiVo) of zone 13. There is a 2 acre

commercial tract near the southwest comer of this zone.

The eastem part of the zone enclosed by Avenue P on the west, 114th Street on the

north, U.S. Highway 87 on the east, and FM 1585 on the south is comprised of

approximately 70 acres (7%) that can be developed. The remainder of this area contains a

heavy mix of commercial, residential, and agricultural uses. The proposed greenbelt

includes approximately 14 acres (U/2%) that wind through open space, exiting at Hwy 87.

The topography is generally flat except in the immediate area surrounding lake #208.

The collector streets mn basically north-south and east-west. The east-west streets

border the north side of the existing residential development and the south side of the

existing commercial area. The collector streets and existing uses divide this zone into

four residential areas totaling approximately 395 acres (41%).

90

Residential area number I is bounded by 114th Street on the north, a collector street

on the east and south, and the existing commercial area on the west.

Residential area number 2 is enclosed by collector streets on the north and west sides.

114th Street on the south side, and the existing residential development.

Residential area number 3 has boundaries of 114th Street on the north. Av enue P on

the east, and collector streets on the south and west sides.

Residential area number 4 is bounded on the north and east by existing land uses, the

south by FM 1585, and the west by Avenue P.

A school is proposed in the middle of the larger secfion.

91


Zone 13 950 acres


No. Acres 68 20 395 467

% of Total 7.2 2.1 41.6 49.1

93

CHAPTER V

MASTER PLAN SUMMARY AND RECOMMENDATIONS

The Master Plan thesis proposes land uses for approximately 8,093 acres div ided into

five land use categories: (1) residenfial uses totaling approximately 5.190 acres, or 64^0

of the plan area; (2) open space/storm water parks, greenbelts, and equestrian park totaling

approximately 1,562 acres, or 19% of the plan area; (3) exisfing land uses totaling

approximately 913 acres, or 11% of the plan area; (4) commercial uses totaling

approximately 325 acres, or 4% of the plan area; and (5) the linear park totaling

approximately 103 acres, or 2% of the plan area.

According to information provided by the City of Lubbock Planning Department, the

number of housing units in a fully developed one square mile area is approximatelv 2000

units (3.13 units/ac), based on 1990 census information, with an average household size

of 3.0 persons. Assuming that housing units in the proposed 5,190 acre residential uses

are similar to the existing housing unit averages, there will be approximatelv 16,245

housing units in a fully developed scenario. Therefore, the rafio of number of housing

units to the number of acres of open space (includes all parks and greenbelts )w ill be

16,245:1,665 or approximately 10:1, or 30 persons per acre of open space.

There, however, is a conceivable scenario where all playa lakes are at flood level.

thereby reducing the number of available, or useable, acres of open space bv 856 acres (a

reduction of 51%). As a result, there will only be 809 acres of useable open space, or a

94

ratio of approximately 20 housing units per acre of useable open space, or 60 persons per

acre of open space.

According to National Recreation and Park Association (NRPA) guidelines, a

community park should provide a minimum of V2 ac. to 1 ac. of open space per 1 ()()()

individuals. A community park is defined as a park 16 ac. to 99 ac. in size serv ing

neighborhoods in a V2 mile to 1 mile radius. Therefore, the open space areas proposed in

the Master Plan are within NRPA guidelines regarding size to population ratios.

An altemative to the NRPA guidelines was expressed by Marsh (1998) who thought

that 30% of useable land (land that is not set aside for special use. such as wildlife

habitat) should be devoted to open space. If this recommendation is adhered to. the studv

area should have 1,897 acres total open space (8,093 ac. in the study area less 856 ac.

covered by water less 915 ac. existing uses x 30%), leaving 4,100 ac. for residential

development (after deducting 325 ac. proposed commercial land uses). Further

calculations will show that if Marsh's recommendafion is used, the ratio of housing units

to acres of open space is 12,833:1,897 or 6.75:1 (20 individuals per acre).

Steiner (1991) showed that performance zoning in Bucks County, Pennsylvania

utilizes similar criteria as does Marsh except that Bucks County requires 20% of useable

land be set aside for open space rather than 30%. If the Bucks Countv criteria are

followed, the study area would have 1,264 acres open space, and 4,733 acres for

residential development, resulting in a housing units to acres of open space ratio ol"

14,814:1,264 or 12:1 (36 individuals per acre).

95

According to the City of Lubbock Planning Department, building pemiits for new

residential constmction in the last five years have averaged approximatelv 500 new

permits yeariy city-wide. At that annual rate, if all new housing construction is limited to

the Master Plan area, it will take approximately 32 years for the area to be fullv

developed, resulfing in a populafion increase of 48,735 individuals by the vear 2030.

As to the public health issues related to EMF. research continues to be funded bv

Congress under the Energy Policy Act of 1992. This continuing research and the

upcoming release of updated data and case studies may provide additional information on

this issue. According to the National Insfitute of Environmental Health and Science, an

upcoming draft report should go to the Secretary of Health and Human Services in

October 1998, who will review the report and forward the final report to Congress in

1999.

This conceptual plan illustrates that: (1) small watersheds and their corresponding

playa lakes can be interconnected by a series of specifically planned greenbelts, (2) these

greenbelts can carry playa stormwater away from individual playas before waters rise to

levels that cause damage to private property, (3) environmentally compatible stormwater

management without the initial expense, and on-going maintenance expenses, of an

underground stormwater management system will be fostered, (4) water quality in the

playa lakes could potentially improve, (5) less surface evaporation and more infiltration

of stormwater will contribute to groundwater recharge, (6) a city-wide open space svstem

that guides a person from one open space area to another instead of hav ing isolated,

incongruous parks, and allows for linkage of neighborhoods will be created, and (7) as

96

EMF are addressed in the Master Plan, the approximatelv 50 to 200 foot wide corridor of

open space on each side of the electrical transmission lines has been allocated as a butter

to potentially mitigate the impact of EMF. The varving width of this E.\1F buffer is

somewhat subjectiv e and its design is driv en by open space and aesthetic issues more

than public health issues. This corridor hopefully provides a greater margin of safet> than

would exist if residential land uses and schools are placed adjacent to the utilitv right-of-

wav. The separation distances from schools to electrical transmission lines range from

approximately 400 feet to 2,500 feet in the zones where the electrical transmission line

corridor exists. As new informafion conceming EMF is obtained, more definitive

guidelines conceming separation distances between electrical transmission lines and

residential land uses can be incorporated into land use planning on the local as well as

national level.

Although this conceptual plan shows that stormwater quality and quantitv can be

controlled through the planning and use of open space and greenbelts. it also brings to

light unanswered questions that deserve to be addressed. Among these questions is what

is the optimum amount of open space in relation to residential development for this area?

Also, can a more substantial EMF buffer be incorporated into the linear park concept

which enhances the open space system and provides ample developmental potential?

There is the awareness, also, that for this concept to work, it must be accepted as a

viable stormwater management and open space plan strategv on a large scale. This basic

concept, therefore, would need to be analyzed on a countv -wide, and regional, watershed

scale.

97

LITERATURE CITED

Electro-magnetic health effects committee. 1992. Health effects of exposure to poweriine-frequency electric and magnefic fields. Public Ufility Commission of Texas.

Field, R.: 0"Shea, M.L.: Chin, K.K. 1993. Integrated stormwater management. Lewis Publishers, Chelsa, MI.

Ferguson, B.K. 1991. Stormwater infiltration. Lewis Publishers. Chelsa. .\ll.

Horton, F.H.: Goldberg, S. 1995. Power frequency magnefic fields and public health. CRC Press, Boca Raton. FL.

Kaiser. Jocelyn. 1996. Panel finds EMFs pose no threat. Science. 274(5289):p.910.

Marsh, William. 1998. Landscape planning: environmental applications. 3rd edition. John Wiley and Sons. New York, NY. Chapter 9. Basin carrying capacity.

Steiner, Frederick. 1991. The living landscape: an ecological approach to landscape planning. McGraw-Hill. Inc.. New York, NY. p.247.

Wanielista, M.P. 1991. Stormwater management, quantitv and quality. Ann Arbor Science Publishers, Inc., Ann Arbor, MI.

Zartman, R. E; Fish, E.B. 1992. Spatial characteristics of playa lakes in Castro County. Texas. Soil Science. 153(l):p.62.

Zartman, R.E; Evans, P.W.; Ramsey, R.H. 1994. Playa lakes on the southem high plains in Texas: reevaluating infiltration. J. Soil and Water Cons. 49(3):p.299.

98

APPENDIX

WATERSHED CALCULATIONS

99

Soil No. and Acres

I - 133.52

5 - 165.87

6 -112.94

16- 41.84

18- 164.87

19- 37.37

23 - 162.53

30 - 340.77

31 - 64.92

42 - 20.12

43 - 18.03

1262.78


Watershed No. 2 1,262.78 acres


% of Total Acres

10.57

13.14

8.94

3.31

13.06

2.96

12.87

26.99

5.14

1.59

1.43

100.00


8

8

8

8

8

8

D

C

C

D

D

Acres in StudvArea

99.70

40.00

47.09

36.45

113.45

8.06

137.00

203.05

18.09

13.10

10.79

726.78

100



Watershed No.2

Area (Am) - 1.97 sq. mi.



Lake no. 94

HSG

8

C

D

D

D

Cover Description

Residential

Residential



Residential

Curve Number

75

83

89

80

87

Area %

51.98

32.13

3.02

6.00

6.87


38.99

26.67

2.69

4.80

5.98

Totals 100.00

CN (weighted) = total product = 79.13 = .7913; Use CN = 79 total area 100

79.13


Runoff depth for curve number of:

40

.84 in.

45

1.24 in.

50

1.68 in.

55

2.12 in.

60

2.60 in.

65

3.10 in.

70

3.62 in.

75

4.15 in.

80

4.69 in.

85

5.25 in.

90

5.82 in.

95

6.41 in.

98

6.76 in.

Runoff, Q = 4.58 in.


101




Soil No. and Acres

% of Total Acres

Hydrologic Acres in Soil Group StudvArea

1 - 115.74

3 - 30.75

5 - 72.30

6-166.09

7 - 184.00

8 - 33.24

16- 5.57

18-74.33

19-62.88

2 3 - 1.82

42 - 29.05

14.92

3.96

9.32

21.42

23.72

4.28

.72

9.58

8.11

.23

3.74

8

8

8

8

8

8

8

8

8

D

D

115.43

0.00

71.60

165.33

0.00

33.24

5.57

74.33

62.88

1.82

28.81

775.77 100.00 559.01

102

Table 20 Watershed Xo. 3 \\ orksheet


\\'atershed No. 3



Rainfall. P (24-hour) - 7 in.

Lake no. 84-.A

HSG

8

D

D

8

Cover Description

Residential

Residential



Curve Number

75

87

89

61

.Area %

82.02

.24

14.00

3.74

Product of C \ X Area

61.52

.21

12.46

2.28

Totals =

CN (weighted) = total product = 76.47 = .7647: total area 100

100.00

UseCN= 76

'6.4'

Runoff depth (Q) in inches for selected CN's and 100 yr. rainfall of


40

.84 in.

45

1.24 in.

50

1.68 in.

55

2.12 in.

60

2.60 in.

65

3.10 in.

70

3.62 in.

75

4.15 in.

80

4.69 in.

85

5.25 in.

90

5.82 in.

inches

95

6.41 in.

98

6.76 in.

Runoff Q = 4.26 in.


103



(drains to playa outside of study area)

Soil No. and Acres

I - 64.85

3 - .15

5 - 158.23

6 - 78.81

18- 31.64

24 - 2.79

4 2 - 12.87

349.34

% of Total Acres

18.56

.04

45.30

22.56

9.06

.80

3.68

100.00


8

8

8

8

8

8

D

Acres in Studv Area

• •

20.96

0.00

140.68

43.74

7.57

1 7")

9.00

224.67

104




Soil No. and Acres

1 - .01

3 - 10.04

5 - 194.70

6 - 145.13

7 - 109.36

16- 8.09

18- 56.25

24 - 5.74

4 2 - 19.47

548.79

% of Total Acres

0

1.83

35.47

26.45

19.93

1.47

10.25

1.05

3.55

100.00


8

8

8

8

8

8

8

8

D

Acres in Studv Area

0.00

.20

193.66

145.13

1.37

8.09

56.25

5.74

19.47

429.91

105



3.275 feet - 100-year flood elevation 136 acre-feet

Soil No. and Acres

1 - 40.34

2 - 56.78

5 -122.16

6 - 6.21

2 3 - 12.52

30- 137.55

4 2 - 10.00

% of Total Acres

10.46

14.73

31.68

1.62

3.25

35.67

2.59


8

8

8

8

D

C

D

.Acres in Studv Area

>4.45

48.5>

122.16

6.21

12.52

135.03

10.00

385.56 100.00 368.92

106

Table 24 W atershed no. 7 Worksheet


Watershed No. 7

Area (Am) - .6 sq. mi.



Lake no. 94-8

HSG

8

C

D

D

8

C

Cover Description

Residential

Residential

Residential




Curve Number

75

83

87

89

61

74

Area %

43.76

30.67

3.25

2.59

14.73

5.00

Product of CN X .Area

32.82

25.46

2.83

2.31

8.99

3.70

CN (weighted) total product total area

Totals

76.11 =.7611

100.00

UseCN= 76 100

76.11


Runoff depth for curv e number of:

40

.84 in.

45

1.24 in.

50

1.68 in.

55

2.12 in.

60

2.60 in.

65

3.10 in.

70

3.62 in.

75

4.15 in.

80

4.69 in.

85

5.25 in.

90

5.82 in.

95

6.41 in.

98

6.76 in.

Runoff. Q = 4.26 in.

Runoff volume = Q x Am x 53.33 = 4.26 x .6 x 53.33 = 136 acre feet

107




Soil No. and Acres

I - 323.00

5 - 75.08

6 - 120.98

18- 126.20

19- 14.04

35- .88

42 - 20.04

680.22

% of Total Acres

47.48

11.04

17.79

18.55

2.06

.13

2.95

100.00


8

8

8

8

8

8

D


323.00

75.08

120.98

126.20

14.04

.88

20.04

680.22

108


Runoff Curve Number and Runofl'

W atershed No. 8 Lake no. 90-A

.Area (.Am) - 1.06 sq. mi.



HSG

8

8

D

D

Cover Description

Residential




Curve Number

75

61

89

80

Area %

86.46

7.59

2.95

3.00

Product of CN X -Area

64.85

4.63

2.63

2.40

Totals =


100.00

UseCN= 75

'4.51

Runoff depth (Q) in inches for selected CN"s and 100 vr. rainfall of 7 inches


40

.84 in.

45

1.24 in.

50

1.68 in.

55

1 p in.

60

2.60 in.

65

3.10 in.

70

3.62 in.

75

4.15 in.

80

4.69 in.

85

5.25 in.

90

5.82 in.

95

6.41 in.

98

6.76 in.

Runoff. Q = 4.15 in.


109




Soil No. and Acres

1 - 135.96

2 - 63.96

5 - 18.10

6 - 2.19

16- 14.68

18- 74.57

30 - 136.96

4 2 - 15.41

461.83

% of Total Acres

29.44

13.85

3.92

.47

3.18

16.15

29.65

3.34

100.00


8

8

8

8

8

8

C

D


135.96

63.96

18.10

2.19

14.68

74.57

136.96

15.41

461.83

no



Watershed No. 9




Lake no. 132

HSG

8

D

C

C

Cover Description

Residential



Residential

Curve Number

75

89

74

83

Area %

67.01

3.33

15.00

14.66


50.26

2.96

11.10

12.17

Totals = 100.00


76.49



40

.84 in.

45

1.24 in.

50

1.68 in.

55

2.12 in.

60

2.60 in.

65

3.10 in.

70

3.62 in.

75

4.15 in.

80

4.69 in.

85

5.25 in.

90

5.82 in.

95

6.41 in.

98

6.76 in.



111




Soil No. and Acres

1 - 36.20

5 - 42.99

17 - 3.81

18 - 70.75

30 - 97.73

42 - 29.06

280.54

% of Total Acres

12.90

15.32

1.36

25.22

34.84

10.36

100.00


8

8

8

8

C

D

.Acres in Studv .Area

36.20

42.99

3.81

70.75

97.73

29.06

280.54

112



Watershed No. 10




Lake no. 90-D

HSG

8

C

8

C

D

Cover Description

Residential

Residential




Curve Number

75

83

61

74

89

Area %

51.73

24.84

3.07

10.00

10.36


38.80

20.62

1.87

7.40

9.22

CN (weighted) = total product = total area

Totals = 100.00

77.91 =.7791; Use CN = 78 100

77.91



40

.84 in.

45

1.24 in.

50

1.68 in.

55

2.12 in.

60

2.60 in.

65

3.10 in.

70

3.62 in.

75

4.15 in.

80

4.69 in.

85

5.25 in.

90

5.82 in.

95

6.41 in.

98

6.76 in.



113

T:!::^ •\.:-m




Soil No. and Acres

I -308.06

5 -268.21

6 - 125.85

18-260.48

19- 18.15

2 3 - 177.77

4 2 - 27.86

1186.38

% of Total Acres

25.96

22.61

10.61

21.96

1.53

14.98

2.35

100.00


8

8

8

8

8

D

D

Acres in Studv Area

164.67

268.21

125.85

204.84

18.15

177.77

27.86

987.35

114



Watershed No. 11




Lake no. 90-8

HSG

8

8

D

D

D

Cover Description

Residential




Residential

Curve Number

75

61

80

89

87

Area %

80.17

2.50

7.50

2.35

7.48


60.13

1.53

6.00

2.09

6.51

Totals =


100.00

UseCN= 76

76.26



40

.84 in.

45

1.24 in.

50

1.68 in.

55

2.12 in.

60

2.60 in.

65

3.10 in.

70

3.62 in.

75

4.15 in.

80

4.69 in.

85

5.25 in.

90

5.82 in.

95

6.41 in.

98

6.76 in.



115




Soil No. and Acres

1 -304.96

5 - 89.66

6 - 148.48

23- 56.43

30- 101.83

35- 14.99

42- 21.90

735.25

% of Total Acres

41.42

12.14

20.14

7.62

13.78

2.01

2.89

100.00

Hvd Soil

rologic Group

8

8

8

D

C

8

D

Acres in Studv Area

301.96

89.66

148.48

56.43

101.83

14.99

21.90

735.25

116

•'•^^ V-«i«1



Watershed No. 12

Area (Am) - 1 sq. mi.



Lake no. 90-C

HSG

8

C

D

8

D

D

Cover Description

Residential

Residential

Residential




Curve Number

75

83

87

61

80

89

Area %

69.06

15.93

4.40

2.75

4.43

3.43


51.80

13.22

3.83

1.68

3.54

3.05

Totals = 100.00

CN (weighted) = total product = 77.12 = .7712; Use CN = _7I total area 100

77.12



40

.84 in.

45

1.24 in.

50

1.68 in.

55

2.12 in.

60

2.60 in.

65

3.10 in.

70

3.62 in.

75

4.15 in.

80

4.69 in.

85

5.25 in.

90

5.82 in.

95

6.41 in.

98

6.76 in.


Runoff volume = Q x Am x 53.33 = 4.37 x 1 x 53.33 = 233 acre feet

117

=r \ v «




Soil No. and Acres

I - 102.87

2 - 65.91

5 - 1.20

18- 43.39

19- 59.55

24 - 13.42

30- 62.70

31 - 43.83

4 2 - 19.92

4 6 - 30.99

% of Total Acres

23.18

14.85

.27

9.78

13.42

3.02

14.13

9.88

4.49

6.98


8

8

8

8

8

8

C

C

D

8

Acres in Studv .Area

^8.60

65.91

1.20

43.39

59.55

13.42

60.54

43.83

19.92

30.99

443.78 100.00 397.35

118

I S L . V ^



Watershed No. 13


Frequency, year- 100


Lake no. 182

HSG

8

D

8

C

C

Cover Description

Residential




Residential

Curve Number

75

89

61

74

83

Area %

64.50

4.49

7.00

5.00

19.01


48.38

4.00

4.27

3.70

15.78

Totals = 100.00

CN (weighted) = total product = total area

76.13 = .7613; Use CN = 76 100

76.13 J



40

.84 in.

45

1.24 in.

50

1.68 in.

55

2.12 in.

60

2.60 in.

65

3.10 in.

70

3.62 in.

75

4.15 in.

80

4.69 in.

85

5.25 in.

90

5.82 in.

95

6.41 in.

98

6.76 in.



119

=_ \%-




Soil No. and Acres

1 - 77.14

5 - 104.50

6 - 141.87

30 - 39.62

4 2 - 11.06

4 3 - 49.92

424.11

% of Total Acres

18.19

24.64

33.45

9.34

2.61

11.77

100.00


8

8

8

C

D

D

Acres in Studv Area

46.63

73.23

141.10

39.13

11.06

49.92

361.07

120



Watershed No. 14




Lake no. 200

HSG

8

D

C

Cover Description

Residential


Residential

Curve Number

75

80

83

Area %

77.19

13.36

9.45


57.89

10.69

7.84

Totals = 100.00

CN (weighted) = total product - 76.42 = .7642; Use CN = 76 total area 100

76.42


Runoff depth for curve number of;

40

.84 in.

45

1.24 in.

50

1.68 in.

55

2.12 in.

60

2.60 in.

65

3.10 in.

70

3.62 in.

75

4.15 in.

80

4.69 in.

85

5.25 in.

90

5.82 in.

95

6.41 in.

98

6.76 in.



121




Soil No. and Acres

1 -512.13

2 -112.26

5 - 96.20

6 - 96.78

2 4 - 16.24

30 - 54.11

4 2 - 14.05

4 6 - 81.96

983.73

% of Total Acres

52.06

11.41

9.78

9.84

1.65

5.50

1.43

8.33

100.00


8

8

8

B

8

8

D

8


200.59

2.45

96.20

70.62

16.24

8.34

1.84

26.10

422.38

122



Watershed No. 15




Lake no. 189

HSG

8

8

D

Cover Description

Residential



Curve Number

75

61

89

Area %

90.24

8.33

1.43


67.68

5.08

1.27

Totals = 100.00


74.08



40

.84 in.

45

1.24 in.

50

1.68 in.

55

2.12 in.

60

2.60 in.

65

3.10 in.

70

3.62 in.

75

4.15 in.

80

4.69 in.

85

5.25 in.

90

5.82 in.

95

6.41 in.

98

6.76 in.


Runoff volume = Q x Am x 53.33 - 4.04 x 1.54 x 53.33 = 332 acre feet

123




Soil No. and Acres

1 - 34.44

5 - 7.54

6 - 25.25

18- 134.97

19- 86.84

2 4 - 8.31

30-257.35

4 2 - 15.21

569.91

% of Total Acres

6.04

1.32

4.43

23.68

15.24

1.46

45.16

2.67

100.00


8

8

8

8

8

8

C

D

Acres in Studv Area

0.01

0.21

0.00

46.64

0.00

8.31

109.62

0.00

164.79

124




Soil No. and Acres

1 -170.54

16- 11.58

18-211.15

2 3 - 25.85

30- 3.77

3 5 - 30.77

4 2 - 12.41

% of Total Acres

36.59

2.48

45.30

5.55

0.82

6.60

2.66


8

8

8

D

C

8

D


53.55

10.22

59.86

25.85

0.59

30.77

12.41

466.07 100.00 193.25

125



Watershed No. 17




Lake no. 208

HSG

8

C

8

D

D

Cover Description

Residential

Residential




Curve Number

75

83

61

80

89

Area %

84.98

.81

6.00

5.55

2.66


63.74

.67

3.66

4.44

2.37

Totals =


100.00

Use CN = 75

74.88



40

.84 in.

45

1.24 in.

50

1.68 in.

55

2.12 in.

60

2.60 in.

65

3.10 in.

70

3.62 in.

75

4.15 in.

80

4.69 in.

85

5.25 in.

90

5.82 in.

95

6.41 in.

98

6.76 in.



126

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STORMWATER MANAGEMENT AND RECREATIONAL MASTER A …