Hydrologic Impact Assessment of Land Cover Change anddoctorflood.rice.edu/sspeed/downloads/LID_2014/... · Hydrologic Impact Assessment of Land Cover Change and . Stormwater Management

The University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249 1

Hydrologic Impact Assessment of Land Cover Change and

Stormwater Management using the Hydrologic Footprint Residence

Dr. Marcio Giacomoni Assistant Professor

Department of Civil and Environmental Engineering

Flow

2014 Low Impact Development (LID) in Houston Workshop Rice University – April 3rd 2014


Hydrologic Impacts of Urbanization • Land cover change and urbanization alters

natural hydrologic flow regime

0

20

40

60

80

100

120

0 20 40 60 80 100 120 140

Flow

Time

Pre-DevelopmentPost-Development

∆t

∆Q


• The effects are more frequent and severe floods which cause: – Erosion – Property losses due to flooding – Loss of habitat/Ecological degradation

• Downstream communities are directly dependent on the: – duration – frequency – magnitude of high and low flows

Effects of Hydrologic Alteration


LIDs and BMPs • Low Impact Development (LID) and Best

Management Practice (BMP) are strategies to mitigate the impacts of urbanization

• BMPs are typically defined as storage facilities: – Detention ponds

• LIDs are structures designed to enhanced infiltration and control runoff generation at the source: – Pervious Pavements – Biogardens/Swales – Infiltration trenches – …

www.metaefficient.com, http://www.wild-wonderings.blogspot.com/ http://www.physics.tamu.edu/NewPB.html, TAMU Campus Masterplan, p 140


Evaluating BMPs and LID • Peak Flow is commonly used to assess impact

of development • Criteria: Pre-development peak flow should not

be exceeded • Qpeak is it sufficient?

Qpeak?


∆t 0

20

40

60

80

100

120

0 50 100 150 200

Q

Time

Pre-DevelopmentPost-DevelopmentReservoir

∆Q

Hydrological Alteration


Hydrologic Footprint Residence • Develop a new metric to quantify the effects

of development in downstream communities that take into account more than just peak flow

• How to represent the increase in runoff and temporal alteration?

Giacomoni, M., Zechman, E., and Brumbelow, K. (2012). ”Hydrologic Footprint Residence: Environmentally Friendly Criteria for Best Management Practices.” J. Hydrol. Eng., 17(1), 99–108.


Hydrologic Footprint Residence • The HFR of a specific storm event and segment

of stream reach is defined as the area of land that is inundated and the duration over which the flood wave passes through the reach.

Time (hr)

Flow

(ft³/

s) Inundated Response Curve

Time (hr)

Inun

date

d Ar

ea (a

cres

) Time (hr)

Wat

er D

epth

(ft)

0

0

2

2

2

4

4

4

3

3

3 𝐻𝐻𝐻 = � 𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼𝐼 𝐴𝐴𝐼𝐼 𝐼 . 𝐼𝐼

𝑇

𝑡=0

t =0

1

1

1

t =1 t =2

t =3

L


Hydrologic Footprint Residence • Evaluate the change of inundated floodplain

areas and the duration of a flood’s residence • Units: Area and Time [acre-hours]


Case Study: Village Creek Watershed • Drainage area: 370 km² • High rates of urbanization

0

10000

20000

30000

40000

50000

60000

70000

Area

(acr

es)

Crops/Grassland/Pasture

Forest/Wetland

High DensityUrban/Transportation

Low Density Urban

Water

1973 1979 1986

1992 2001 2009


Modeling Framework CA Land Cover Change

Model

Hydrologic Model

Hydraulic Model

Initial Land Cover

Rainfall (Design Storm)

Projected Land Cover

Runoff Hydrographs

Stream Geomorphology (Cross-Sections)

Water Surface Elevation

HFR

Giacomoni, M.H., G. Ryan, E.M. Zechman “Hydrologic Impact Assessment of Land Use Change Using the Hydrologic Footprint Residence”. J American Water Resources Association (Accepted).


( ) ( ) ( )1( , ) ( , ) ( , ) ( , ) ( , )1 1 1t t tx y x y x y x y x yL N DMR DmR DCa Rdα β γ µ ε+ = × + × − + × − + × − + ×

• Simulates the sprawl of urban areas • Likelihood of a cell to change its state to urban is a

function of: Number of

Developed Neighbors

Normalized Distance to

Major Roads

Normalized Distance to Minor

Roads

Random Variable

Normalized Distance to Central

Areas

Existing Development New Development

Time t Time t+1

( )1( , )If 1 Change State to Urbantx yL tθ+ ≥ + →

Cellular Automata Land Cover Change Model


Land Cover Change: 1973 - 2050

0%10%20%30%40%50%60%70%80%90%

100%

1970 1980 1990 2000 2010

Urb

an L

and

Cov

er

Predicted Observed


Modeling/HFR Calculation • Hydrologic Model:

– SWAT – 95 subcatchments – Hourly time step

• Hydraulic Model: – HEC-RAS – 22.14 Km – 124 cross sections

Legend Village Creek Watershed


Legend Water Bodies Urban Residential Commercial/Transportation Forest Agriculture

Management Scenarios • Existing Development • Future Development • Future Development/BMP • Future Development/LID

2010

Legend Village Creek Watershed

2035 Legend

Water Bodies Urban Residential Commercial/Transporation New Urban Development Forest Agriculture


Hydrographs and Inundated Land Curves (2-yr storm)

0

500

1000

1500

2000

0 20 40 60 80 100 120

Flow

(cfs

)

Time (hours)

Present Future BMP LID

50

70

90

110

130

150

170

0 20 40 60 80 100 120

Inun

date

d Ar

ea (A

cres

)

Time (hours)

Present Future BMP LID


Peak Flow and HFR Results

Scenario

2-yr storm

Peak Flow

(cfs)

Reduction

(%)

HFR

(ac-hrs)

Reduction

(%)

Existing 1737 - 10,580 -

Future 1922 10.6% 10,913 3.1%

Future/BMP 1393 -19.8% 10,987 3.8%

Future/LID 1783 2.6% 10,628 0.4%


Peak Flow and HFR Results

Scenario

100-yr storm

Peak Flow

(cfs)

Reduction

(%)

HFR

(ac-hrs)

Reduction

(%)

Existing 6735 - 28,257 -

Future 7425 10.2% 30,979 9.6%

Future/BMP 5606 -16.8% 28,267 0.0%

Future/LID 6904 2.5% 28,637 1.3%


Observations • 2-yr storm

– Detention pond has lower peak flow than LID – LID has lower HFR than detention pond

• 10-yr and 100-yr storms – Detention pond has lower peak flow than LID – Detention pond has lower HFR than LID

• Adoption of combination of LID and BMP controls a wide spectrum of storms: – Better mimicking smaller and frequent storms – Providing necessary flood control during intense events


Stormwater Footprint Calculator (SFC) • Scott et al. (2014) developed an SFC:

– Education tool developed to improve knowledge and change attitudes and behavior regarding stormwater sustainability

• Participant’s answer about lot/neighborhood- level land use is used to compute HFR and Peak Flow

Scott T., Politte A., Saathoff S., Collard S., Berglund E., Barbour J., & Sprintson A. 2014. An evaluation of the Stormwater Footprint Calculator and the Hydrological Footprint Residence for communicating about sustainability in stormwater management. Sustainability: Science, Practice, & Policy 10(1) Published online Feb 21, 2014. http:///archives/vol10iss2/1210-048.scott.html


Stormwater Footprint Calculator (SFC) • An experiment (N = 510) undergraduate students was

used to test the SFC as a tool for: – communicating about stormwater management – compare HFR vs Peak Flow

• Results support: – improves knowledge about the causes of stormwater

runoff – LID technologies – HFR is a viable alternative to conventional engineering

metrics for communicating a stormwater footprint

Scott T., Politte A., Saathoff S., Collard S., Berglund E., Barbour J., & Sprintson A. 2014. An evaluation of the Stormwater Footprint Calculator and the Hydrological Footprint Residence for communicating about sustainability in stormwater management. Sustainability: Science, Practice, & Policy 10(1) Published online Feb 21, 2014. http:///archives/vol10iss2/1210-048.scott.html


In Summary • A modeling framework that includes a Land Cover

Change model, hydrologic, and hydraulic modeling to assess impact of urbanization and stormwater management

• A new metric designed to assess the impacts of urbanization on the hydrological flow regime by measuring inundated area and timing of flow

• HFR can better quantify alterations of the flow regime compared to the use of the peak flow only

• HFR can help better communicate stormwater concepts such as LID to the public


QUESTIONS?

[email protected]

Documents

Hydrologic Impact Assessment of Land Cover Change anddoctorflood.rice.edu/sspeed/downloads/LID_2014/... · Hydrologic Impact Assessment of Land Cover Change and . Stormwater Management