Hydrology Design

471 BERKELEY DRIVECLEMSON, SC

BE 3220 - Hydrology Design ProjectKira Bartlett, Raymond Middleswarth, Ashleigh Hough

April 21, 2015

LOCATION (GEOGRAPHICAL)

LOCATION (TOPOGRAPHICAL)

LOCATION

CURRENT PROBLEM

• Two hills– “Big Hill”: 52.5 feet long with a 20% slope– “Small Hill”: 82.5 feet long with a 5% slope

• Rill formation where the hill bases meet

• Runoff moves through the adjacent shed and occasionally causes a creek to form

PROJECT GOALS

• Transform the property into a community garden

• Minimize erosion and runoff

• Reduce the runoff and sediment volume entering the shed – Dry conditions necessary to store equipment– Reduce cleaning after rainstorms

PROPERTY DATA

Modeled as Two Separate Hillslopes

Cropping Factor: 0.01225% Canopy of Tall Weeds80% Ground Cover

Soil Type: Starr Loam (K=0.37)(via Web Soil Survey)

USCLE: CURRENT SITUATIONSmall Hill Big Hill

R 250 250

K 0.37 0.37

LS 0.601 2.283

C 0.012 0.012

P 1 1

T 0.667 tons/acre/year

2.53 tons/acre/year

Rate of Annual Soil Loss: 3.2 tons/acre/yearTotal Annual Soil Loss: 0.233 tons

WEPP: CURRENT SITUATION

Slope: 52.5 ft. at 20% slope Profile Width of 54 feet

Climate: Clemson College, SCManagement: Grass (cont.)

Average Annual Runoff: 5.29 inAverage Annual Soil Loss:

1.758 tons/acre

Slope: 82.5 ft. at 5% slope Profile Width of 54 feet

Climate: Clemson College, SCManagement: Grass (cont.)

Average Annual Runoff: 4.58 inAverage Annual Soil Loss:

0.996 tons/acre

Big Hill Small Hill

Rate of Annual Soil Loss: 2.754 tons/acreTotal Annual Soil Loss: 0.2163 tons

PROPOSED SOLUTIONFour Terraces

Open Channel Flow

USLE: PROPOSED SOLUTION Terrace 1 Terrace 2 Terrace 3 Terrace 4

R 250 250 250 250K 0.37 0.37 0.37 0.37

LS 0.442 0.442 1.45 1.45

Crop Seq. CCCCC SSSM CCCM CAAA

C 0.03 0.18 0.02 0.02

P 1 1 1 1

T (tons/acre)

1.226 7.359 2.683 2.683

SDR 10% 16%

T (tons/acre)

0.7482 0.497


WEPP: PROPOSED SOLUTION

Terrace 1 Terrace 2 Terrace 3 Terrace 4Slope

Characteristics

40 ft. with 5% slope




Management Corn No Till Soybean No Till

Corn No Till Alfalfa with Cuttings

Average Annual Soil

Loss (tons/acre)

2.367 2.625 2.618 3.599

SDR 10% 16%

T (tons/acre) 0.2862 0.5110

AssumptionsClimate: Clemson College, SCProfile Width: 54 feet


ANALYSIS OF PROPOSED SOLUTION

USLECurrent Situation

– Rate of Soil Loss: 3.2 tons/acre– Total Annual Soil Loss: 0.233

tonsProposed Solution

– Rate of Soil Loss: 1.246 tons/acre

– Total Annual Soil Loss: 0.1089 tons

WEPPCurrent Situation

– Rate of Soil Loss: 2.754 tons/acre– Total Annual Soil Loss: 0.2163

tonsProposed Solution

– Rate of Soil Loss: 0.7972 tons/acre

– Total Annual Soil Loss: 0.0625 tons

Erosion Reduction: 61% Erosion Reduction: 71%

OPEN CHANNEL DESIGN• Use of WEPP Model (10-year Storm)

– Big Hill Peak Rate: 5.6 in/hr– Small Hill peak Rate: 4.8 in/hr

• Parabolic Channel Design • Vegetation Lined – Grass Mixture

– Short Vegetation (2-6 inches)• Slope of Profile Width: 0.2 %

10-Year StormQ= 0.000257 cfs

Duration of 1 Day:Total Runoff Volume: 166.4 gallons

ALTERNATIVE DESIGN OPTIONS

• Different Terracing Setups– Change number of Terraces and Terrace Lengths– Include terraces with grass or meadow

• Contouring or Contour Strip-cropping

• Some methods found to be more effective in erosion control, but less practical and/or profitable

SUMMATION

• 4 Terraces– Reduces Sediment Loss by 60-70%– Allows for use of land as a garden

• Open Channel Flow– Redirects runoff and sediment away from the shed

OVERALL: Balances Sediment Loss with Practicality and Economics to

obtain Project Objectives

REFERENCES“Web Soil Survey.” Web Soil Survey. USDA: Natural Resources Conservation Service, n.d.

Owino, Tom. “Open Channel Hydraulic” Handout. Small Watershed Hydrology and Sedimentology. Clemson University. April 2015. Print (unpublished).

Owino, Tom. “Soil Erosion” Handout. Small Watershed Hydrology and Sedimentology. Clemson University. February 2015. Print (unpublished).

Water Erosion Prediction Project (WEPP)

Education

Hydrology Design