Surface Water Balance in the Pecos River Basin

Surface Water Balance in the Pecos River Basin Sedat Yalcinkaya April 28, 2010 Pecos River, near Langtry, Val Verde County, Texas

Too much water but not when and where it is needed! � IPCC report “Climate Change and Water”, 2008 � UN Millennium Development Goals “Food and Water Security” � The EU Water Framework Directive Integrated River Basin Management for Europe

Water Resources Planning and Management � Surface Water Balance in the Pecos River Basin with Arc. GIS � Runoff Analysis in the study area � Application of WEAP v All the calculations were made for 1990 except runoff analysis

Study Area 33. 02 and 29. 69 N Latitude 104. 65 and 101. 14 W Longitude WATERSHEDS (HUC_8) 13070001 6454. 582529 13070003 2913. 223075 13070004 5074. 004481 13070005 1831. 660091 13070006 3833. 113807 13070007 16414. 37423 13070008 4962. 616022 13070009 2505. 34438 13070010 1997. 452143 13070011 2828. 999238 13070012 TOTAL BASIN AREA 2573. 636942 AREA (KM 2) 51389. 006960

Data Sources � CRWR Database � NRCS, Geospatial Data Gateway � NHDPlus � NCDC � NASA, Land Data Assimilation System

Processing the Climate Data 32 km cell size

Processing the Soil Data Layer Thickness Depth to Top Depth to Bottom 1 5 cm (2 in) 0 cm (0 in) 5 cm (2 in) 2 5 cm (2 in) 10 cm (4 in) 3 10 cm (4 in) 20 cm (8 in) 4 10 cm (4 in) 20 cm (8 in) 30 cm (12 in) 5 10 cm (4 in) 30 cm (12 in) 40 cm (16 in) 6 20 cm (8 in) 40 cm (16 in) 60 cm (24 in) 7 20 cm (8 in) 60 cm (24 in) 80 cm (31 in) 8 20 cm (8 in) 80 cm (31 in) 100 cm (39 in) 9 50 cm (20 in) 100 cm (39 in) 150 cm (59 in) 10 50 cm (20 in) 150 cm (59 in) 200 cm (79 in) 11 50 cm (20 in) 200 cm (79 in) 250 cm (98 in) First Bucket Second Bucket The resolution is 1/8 degree (~140 km 2 per grid cell)

Simple Surface Water Balance with Arc. GIS P= Precipitation E= Evaporation Q= Naturalized Flows

350 300 250 200 150 100 Evaporation, mm 100 200 100 0 400 50 0 Sub Watershed r br y ua ry M ar ch Ap ril M ay Ju ne Ju Au ly Se gu pt st em b O er ct N ob ov er e D mbe ec em r be r 300 nu a 600 Precipitation, mm 120 Fe Annual Precipitation, mm 400 Ja 0 13 001 07 0 13 003 07 0 13 004 07 0 13 005 07 0 13 006 07 0 13 007 07 0 13 008 07 0 13 009 07 0 13 010 07 0 13 011 07 00 12 13 07 700 nu Fe ary br ua r M y ar ch Ap ril M ay Ju ne Ju Au ly Se gu pt st em b O er ct N ob ov er e D mb ec er em be r Annual Evaporation, mm 500 Ja 13 07 0 13 00 07 1 0 13 00 07 3 0 13 00 07 4 0 13 00 07 5 0 13 00 07 6 0 13 00 07 7 0 13 00 07 8 0 13 00 07 9 0 13 01 07 0 0 13 01 07 1 00 12 Precipitation and Evaporation 80 60 40 20 0 Sub Watershed Months 50 45 40 35 30 25 20 15 10 5 0 Months

Water Balance 6000 4000 3000 Precipitation 2000 Evaporation Net Outflow 4000 3500 2000 1500 1000 500 Se gus t pt em be r O ct ob N ov er em b D ec er em be r Au -1000 Ju -500 ly 0 ry br ua ry M ar ch Ap ril M ay Ju ne It is likely that considerable amount of water was stored in the reservoirs exist along the basin. 3000 Fe Months Change in Storage, Mm 3 Fe Ja nu ar br y ua ry M ar ch Ap ril M ay Ju ne Ju Au ly Se gu pt st em b O er ct N ob ov er e D mb ec er em be r 0 nu a 1000 Ja Volume, Mm 3 5000 Months

Months r m be ec e D ob er ct ov e N O r st gu em be Se pt Au ly Ju Ju ne M ay ril Ap h ar c M y ry br ua r Fe nu a Ja Volume, Mm 3 Runoff Analysis 60 50 40 30 20 10 0

Rainfall vs Runoff 1. 4 1. 2 Runoff, mm/month R 2 = 0. 5126 1 0. 8 0. 6 0. 4 0. 2 0 0 20 40 60 Rainfall, mm/month 80 For example; for a 40 mm rainfall can cause a 0. 4 mm runoff 100 120

Hydrologic Modeling with WEAP

Adding Data to WEAP

WEAP Results

1990 values in mm Conclusion Precipitation Evaporation Mean 35. 4525 21. 06 0. 46 Max 107. 9 43. 92 1. 2 Most of the precipitation occurs in July, Min 5. 76 4. 88 August and September � Precipitation gets the lowest level in winter � Maximum evaporation occurs in August, September and October � Maximum runoff occurs in September and October � � The Runoff water balance for 1990 indicates shortage of water in May, June and December. 0. 18

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