Ponds and Dams in the Pedernales River Basin

Ponds and Damsin thePedernales River Basin

John MiddletonCE 394K.2May 2005

Project Goal

Develop a simple water balance model to predict water levels in various storage structures. Simple to use Data readily available Works

Challenges How to calibrate

Motivation

Ponds and dams on family property

Roy Bedichek’s idea of “little waters” as habitats

Approach

Analyze a progression of storage systems Cistern Tank Dam on intermittent

creek Dam on river

Pedernales Watershed

Pedernales River Basin: 1294 mi²

You Are Here

Upper Fall Creek

Tools and Data

Tools ArcGIS

Watershed areas Landcover estimates

Mathcad Infiltration model

Excel Water balance

calculations

Data Precipitation

NCDC, TWDB

Evaporation TWDB

Wells TWDB

Flow USGS

Miscellaneous – LCRA pubs, textbooks, Dad

Plan A

Develop a monthly water balance in Excel Infiltration – Mathcad Green-Ampt 2-layer

model Runoff estimates using SCS curve Estimate demand based on published

livestock consumption numbers Assume storage volumes have uniform depth

and vertical sides

Water Balance

Cistern P - E - D

Earthen Tank P - E - I - D + R

Dam on Creek P - E - I - D + R + B

P = Precipitation E = Evaporation D = Demand I = Infiltration R = Runoff B = Base Flow In

Plan B

Use daily rain data

1st Approach used mean monthly data Problems with SCS model – single rain value

not representative of the rain distribution

Tank Catchment

Drainage: 235 acres

Tank depth: 8ft Tank area: 1000

ft2

Google Maps is Cool

Spreadsheet Model

Cistern/Tank Model

Spicewood Cistern/Tank 2000 - 2002

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Cistern with demand

Earthen tank

Earthen tankwith demand

Drainage: 235 acresDepth: 8ftArea: 1000 ft2

Start Depth: 8ft

Cistern/Tank Model

Spicewood Cistern/Tank 2000 - 2002

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Cistern with demand

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Earthen tankwith demand

Drainage: 235 acresDepth: 8ftArea: 1000 ft2

Start Depth: 0ft

Cistern/Tank ModelDrainage: 235 acresDepth: 8ftArea: 1000 ft2

Start Depth: 0ft

% of Runoff Detained

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% full

Upper Fall Creek

Dam Catchment Drainage: 3852 acres Depth: 6ft Tank area: 23,774 ft2

Dam Model

Spicewood Lower Dam 2000 - 2002

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Dam with Demand

Drainage: 3582 acresDepth: 6ftArea: 23,774 ft2

Start Depth: 6ft

Conclusions

Cistern/Tank model appears reasonable Dam model

Difficult to calibrate Creek baseflow not known Runoff/infiltration model may be overly

simplistic Excel is good, but I’m tired of it

Model Improvements

Infiltration model – convert to VB routine SCS method needs daily data Spring flow estimates Shape of storage structure NARR for evaporation Doppler for rainfall Improved runoff method

Questions?

Pedernales Basin

Tank ModelP = Precipitation

Input Parameters E = EvaporationStorage Area Demand D = Demand

Area 1000 ft2 Number Horses 10 I = Infiltration 262500 m2Depth 8 ft Total demand 402 gal/mon R = Runoff 2824500

Volume 8000 ft3

Starting Depth 0 ft Infiltration 12 in/mon

Drainage area 1.02E+07 ft2 235.13 acres

CisternCistern with demand Earthen tank

Earthen tankwith demand Dam

Dam with Demand

PPrecipitation

(in)

EEvaporation

(in)

IInfiltration

(in)

DDemand

(ft3)

RRunoff

(in)

BBaseflow

ft3

RRunoff

(ft3) P-E (in)P-E Level

(ft)P-E-D Level

(ft)P-E-I+R Level

(ft)

P-E-I+R-D Level

(ft)

P-E-I+R+B Level

(ft)

P-E-I+R-D+B Level

(ft)

0.00 0.00 0.00 0.00 0.00 0.00Jan-2000 1.27 3.98 12 402.00 0 0 0 -2.71 0.00 0.00 0.00 0.00 0.00 0.00Feb-2000 1.75 4.03 12 402.00 0 0 0 -2.28 0.00 0.00 0.00 0.00 0.00 0.00Mar-2000 2.55 4.73 12 402.00 0.07945739 0 67,691 -2.18 0.00 0.00 8.00 8.00 8.00 8.00Apr-2000 1.97 5.52 12 402.00 0 0 0 -3.55 0.00 0.00 6.70 6.30 6.70 6.30

May-2000 3.75 7.36 12 402.00 0.306640388 0 261,233 -3.61 0.00 0.00 8.00 8.00 8.00 8.00Jun-2000 3.71 8.82 12 402.00 0.059153155 0 50,394 -5.11 0.00 0.00 8.00 8.00 8.00 8.00Jul-2000 0.28 10.31 12 402.00 0 0 0 -10.03 0.00 0.00 6.16 5.76 6.16 5.76

Aug-2000 0.83 9.98 12 402.00 0 0 0 -9.15 0.00 0.00 4.40 3.60 4.40 3.60Sep-2000 1.14 7.05 12 402.00 0 0 0 -5.91 0.00 0.00 2.91 1.70 2.91 1.70Oct-2000 2.86 4.49 12 402.00 0 0 0 -1.63 0.00 0.00 1.77 0.17 1.77 0.17Nov-2000 7.58 4.67 12 402.00 0.76820835 0 654,452 2.91 0.24 0.00 8.00 8.00 8.00 8.00Dec-2000 1.55 2.52 12 402.00 0.000360092 0 307 -0.97 0.16 0.00 7.23 6.82 7.23 6.82Jan-2001 3.3 2.49 12 402.00 0.04333872 0 36,921 0.81 0.23 0.00 8.00 8.00 8.00 8.00Feb-2001 1.51 2.01 12 402.00 0.005800189 0 4,941 -0.5 0.19 0.00 8.00 8.00 8.00 8.00Mar-2001 7.32 2.82 12 402.00 1.215378081 0 1,035,404 4.5 0.56 0.00 8.00 8.00 8.00 8.00Apr-2001 2.71 3.61 12 402.00 0.130569521 0 111,235 -0.9 0.49 0.00 8.00 8.00 8.00 8.00

May-2001 4.14 5.88 12 402.00 0.059607979 0 50,781 -1.74 0.34 0.00 8.00 8.00 8.00 8.00Jun-2001 1.05 7.21 12 402.00 0 0 0 -6.16 0.00 0.00 6.49 6.08 6.49 6.08Jul-2001 0.75 7.92 12 402.00 0 0 0 -7.17 0.00 0.00 4.89 4.09 4.89 4.09

Aug-2001 3.33 8.52 12 402.00 0.002758885 0 2,350 -5.19 0.00 0.00 5.81 4.60 5.81 4.60Sep-2001 2.27 5.2 12 402.00 0 0 0 -2.93 0.00 0.00 4.56 2.95 4.56 2.95Oct-2001 4.27 3.96 12 402.00 0.593879432 0 505,937 0.31 0.03 0.00 8.00 8.00 8.00 8.00Nov-2001 11.79 2.3 12 402.00 5.133433154 0 4,373,271 9.49 0.82 0.39 8.00 8.00 8.00 8.00Dec-2001 1.91 1.88 12 402.00 0 0 0 0.03 0.82 0.00 7.00 6.60 7.00 6.60Jan-2002 0.89 1.91 12 402.00 0 0 0 -1.02 0.73 0.00 5.92 5.11 5.92 5.11Feb-2002 0.77 2.53 12 402.00 0 0 0 -1.76 0.59 0.00 4.77 3.56 4.77 3.56Mar-2002 1.29 3.04 12 402.00 0 0 0 -1.75 0.44 0.00 3.63 2.02 3.63 2.02Apr-2002 0.45 5.08 12 402.00 0 0 0 -4.63 0.06 0.00 2.24 0.23 2.24 0.23

May-2002 1.8 4.96 12 402.00 0.072393497 0 61,673 -3.16 0.00 0.00 8.00 8.00 8.00 8.00Jun-2002 4.91 7.55 12 402.00 0.830267276 0 707,321 -2.64 0.00 0.00 8.00 8.00 8.00 8.00Jul-2002 9.91 5.52 12 402.00 1.709034674 0 1,455,960 4.39 0.37 0.00 8.00 8.00 8.00 8.00

Aug-2002 0.87 6.21 12 402.00 0 0 0 -5.34 0.00 0.00 6.56 6.15 6.56 6.15Sep-2002 3.17 6.13 12 402.00 0.302487326 0 257,695 -2.96 0.00 0.00 8.00 8.00 8.00 8.00Oct-2002 6.44 4.51 12 402.00 0.239539602 0 204,068 1.93 0.16 0.00 8.00 8.00 8.00 8.00Nov-2002 2.91 3.95 12 402.00 0.051287948 0 43,693 -1.04 0.07 0.00 8.00 8.00 8.00 8.00Dec-2002 4.5 3.44 12 402.00 0.194187525 0 165,432 1.06 0.16 0.00 8.00 8.00 8.00 8.00

mon avg 37.17 60.70 144 4824 3.93

CisternCistern with demand Earthen tank

Earthen tankwith demand

Earthen tankwith demand Dam

Dam with Demand

Earthen tankwith demand

Spicewood Cistern/Tank 2000 - 2002

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Earthen tankwith demand

Runoff and Spill Flows

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Flo

w (

cfs) Precipitation

Spill cfs

Runoff

Drainage: 235 acresDepth: 8ftArea: 1000 ft2

Start Depth: 0ftCistern/Tank Model