Understanding a Unique Desert Aquatic Ecosystem: Hydrologic Analysis of the Cuatro Ci

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Understanding a Unique Desert Aquatic Ecosystem
Hydrologic Analysis of the Cuatro Ciénegas
Basin, Coahuila, Mexico
Brad Wolaver, Ph.D. Aspirant in
HydrogeologyDepartment of Geological
SciencesDecember 2, 2004
Photo by Robin Havens
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• National preserve
• 200,000 acres
• gt 70 native species
• gt 100 springs
• Sustainable water?
• Rio Grande

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Fractured Limestone
Valley Fill Alluvium
Springs
After Steve Barnett
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Photo by Dean Hendrickson
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Photo by Dean Hendrickson
Photo by Dean Hendrickson
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Photo by Robin Havens
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FISH
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Photo by Suzanne Pierce
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PROJECT GOALS

1. Stream network delineation
2. Fracture analysis recharge pathways
3. Populate geodatabase discharge canal time series

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WHY IMPORTANT?

• Hydrologic cycle poorly understood
• Ground water declines (Hendrickson, 2004)
• Surface water diversions (Lesser y Associados,
  2001)
• No water budget
• Plan optimal water resource management-
  Long-term economic health
• - Agriculture, ecotourism, fish/species

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DATA SOURCES

• DEM USGS
• Springs Profauna
• Canal Discharge Lesser y Associados, 2001
• Aerial Photos1 W.L. Minckley
• Roads1 Universidad Autonóma Nácional de Mexico
  (UNAM)
• 1. Compiled by Moline, A.B., 2002

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1. STREAM NETWORK

• Understand
• Surface water - pre-development
• Recharge pathways - mountain fractures

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SRTM 90 m2 Red no data cells
Elev (m)
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Grid to Points Spline Interpolation
Elev (m)
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Elev (m)
Study Area Filled DEM
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1km2 drainage area Good, some problems
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2. FRACTURE ANALYSIS

• Aerial photos
• - Map fractures in ArcGIS
• Photo resolution insufficient!
• Distribution streams, alluvial fans, springs

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Resolution 30 m2

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Photo resolution insufficient. Need field mapping.
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Green dots springs Distribution f (stream
density) ?
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3. CANAL DISCHARGE

• Populate geodatabase - historical data
• Only 1 measurement ! (Lesser, 2001)
• Install long-term gage

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Canal outflow 1,700 L/SEC 60 CFS 43,000
AF/YR (Lesser y Associados, 2001) Populate
database long-term data
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CONCLUSIONS

• Stream network good, but
• Internal drainage, GW decline stream capture
• Fracture analysis
• Photo resolution need field mapping
• Springs, alluvial fans, streams addl. study
• Diversion canal discharge
• Install long-term gage quantify water budget,
  mgmt. recs.