Presented by Ralf Topper, CPG 30 th Colorado Water Workshop July 28, 2005

…… The value of reservoir water and ground water is clearly realized, and we all recognize the need for additional storage …….

Sustainable water management relies on the ability to store water. But the opportunities for construction of large new reservoirs are dwindling. Ground water will play a critical role in meeting future demands through conjunctive use strategies.

TIMING OF SUPPLY / DEMAND Demand

The Hydrologic Cycle Colorado Supreme Court Justice, Greg Hobbs Sea to the river, feed me River to the aquifer, fill me Aquifer to the earth, hold me Earth to the clouds, seed me Clouds to the wind, stir me Wind to the sea, rinse me Earth to the aquifer Aquifer to the river River to the sea Sea to the wind Wind to the clouds Clouds to the earth Seed me Stir me Rinse me Feed me Fill me Hold me

The Hydrologic Cycle

Surface Water / Ground Water Interaction High Ground Water = Flow to Stream Low Ground Water = Flow to Aquifer

AUGMENTATION CONCEPT

It has been locally implemented in Colorado since 1940 and the subject of numerous state and federal studies.YES! Can We Store Water Underground?

ACTIVE ARTIFICIAL RECHARGE IN COLORADO Augmentation in the Lower South Platte River Basin Conjunctive Use in the San Luis Valley ASR in the Denver Basin Small Miscellaneous Sites Regulate Water Supply and Manage Water Quality

By Implementing Artificial Recharge How Do We Store Water Underground –

SURFACE INFILTRATION DRY

SUBSURFACE INFILTRATION

DIRECT INJECTION CONFINED AQUIFER

BENEFITS OF AQUIFER STORAGE  Minimal or No Evaporative Losses  Minimal Environmental Impacts  Less Permitting Issues  Greater Location Opportunities  Significantly Lower Capital Costs  Shorter Implementation Timeframe  Ability to Stage Construction to Meet Demand

OBJECTIVES OF AQUIFER STORAGE  Management of Water Supplies (seasonal, long-term, emergency)  Legal Obligations and Water Rights (augmentation, interstate agreements)  Manage/Mitigate Water Quality (soil-aquifer treatment, water reuse/treated effluent, industrial controls)  Aquifer Restoration (water levels, subsidence)  Environmental Protection (instream habitat, species recovery, wetlands maintenance/enhancement)

Aquifer Storage Potential Based on Aquifer Properties:  Areal extent  Depth  Saturated Thickness  Hydraulic Conductivity  Storage Coefficient  Head Freeboard

San Luis Valley Lower South Platte Bijou Creek Lower Arkansas Big Sandy Creek Kiowa Creek Top Candidates Unconsolidated Aquifers

Top Candidates Consolidated Aquifers

WATER SUPPLY VS. DEMAND SUPPLY > DEMAND SUPPLY < DEMAND

 Artificial recharge technologies are proven and have been implemented in Colorado on an individual basis.  Sustainable water management relies on the ability to store water. A viable alternative to construction of new surface water reservoirs is the storage of water below ground in aquifers.  Favorable hydrogeologic conditions exist in unconsolidated and consolidated aquifers to implement large-scale artificial recharge projects throughout Colorado  In addition to managing water supplies, aquifer storage projects can meet a number of water resource objectives.

An aquifer is a ground-water reservoir composed of geologic units that are saturated with water and sufficiently permeable to yield water in a usable quantity to wells and springs

Consolidated Sedimentary Bedrock Aquifers Located throughout the state Large areal extent and available head freeboard Can be non-tributary Good for long-term storage Deep - Often Confined Small storage coefficient and lower yield Recharge technique application limited Pro’s: Con’s: – Sandstone Layers in Older Formations

Unconsolidated Sedimentary Aquifers Located along all state’s major rivers Large storage coefficient & high yield Shallow, amenable to multiple recharge techniques Near Agricultural Areas and Urban Areas Limited Areal Extent Shorter Retention Times Tributary to Surface Water Pro’s: Con’s: