In the Denver Basin Bedrock Aquifers

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In the Denver Basin Bedrock Aquifers
A Review of Recent Water Level Changes
Daniel O. Niemela and Christopher J. Sanchez
Bishop-Brogden Associates, Inc
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Overview

• Denver Basin Aquifer Hydrogeology
• Example Hydrograph
• Maps of Decline Rates in Each Aquifer
• Water Use Management

Bishop-Brogden Associates, Inc
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Denver Basin Aquifers

• Confined Aquifer System
• Heterogeneous
• Major Water Source for Front Range Development
• Non-Renewable Resource
• 50k - 100k af/yr Pumping (SEO and Others)
• Developed with Municipal Style Wells (50 800
  gpm)
• Substantial Drilling Cost

Source USGS HA-730-C
Bishop-Brogden Associates, Inc
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Denver Basin Aquifers

• Interbedded Sandstone, Shale and Clay Aquifers
• Dawson Aquifer
• Limited Extent
• Denver Aquifer
• Discontinuous Sands
• Arapahoe Aquifer
• Most Productive
• Laramie-Fox Hills Aquifer
• Widespread

Source USGS HA-730-C
Bishop-Brogden Associates, Inc
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Water Level Data

• Data Sources
• Colorado Division of Water Resources Data (Annual
  Report)
• Municipalities (Unpublished)
• Criteria
• Consistent Water Level Data
• Well Completed in a Single Aquifer

Bishop-Brogden Associates, Inc
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Water Level Decline

• Well-to-Well Impacts
• System not at Steady State
• Decreased Available Drawdown
• Decreased Well Yield
• Increased Pumping Costs
• Increased Maintenance

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Dawson Aquifer

• Decline Rates Between zero and 10 feet per year
• Greatest Decline near Fringe and Front Range
  Urban Corridor
• Some Ground Water Level Rises Recorded

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Denver Aquifer

• Decline Rates Between zero and 40 feet per year
• Greatest Decline Rates near Centers of Pumping
• Inconsistent Data
• Discontinuous Sand Lenses

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Arapahoe Aquifer

• Decline Rates Between zero and 50 feet per year
• Greatest Decline Rates are in South Metro Denver
• Most Productive Aquifer
• High Decline Rates are Not Basin Wide
• Some Ground Water Level Rises Recorded
• Denver Metro
• Less than 5 ft/yr rise
• Water Level Above Top of Aquifer at Most
  Locations

Bishop-Brogden Associates, Inc
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Laramie-Fox Hills Aquifer

• Decline Rates Between zero and 40 feet per year
• More Widespread Declines
• Water Level Above Top of Aquifer at Most Locations

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Trends

• High Decline Rates are Localized
• Result of Sole Reliance on Denver Basin Water
• Well-to-Well Interference
• Complex Nature of the Aquifers
• Anomalies in Denver Aquifer
• Result of Discontinuous Aquifer Sands?

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Management

• Good Water Level Record Keeping
• Project Future Water Levels
• Evaluate Timing for Renewable Supplies
• Efficient Water Use
• Reuse
• Develop Renewable Supplies
• Conjunctive Use
• Aquifer Storage Recovery (ASR)

Bishop-Brogden Associates, Inc
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Conclusions

• Denver Basin Water Level Declines are Occurring
• Declines are Localized in some Aquifers
• Greatest Declines near Greatest Pumping
• Supply System Planning may Extend Usable Life of
  Resource
• Municipalities are Actively Pursuing Renewable
  Supplies

Bishop-Brogden Associates, Inc