Progress 07/01/01 to 06/30/04
Outputs
The intent of managed recharge is to redistribute water in time. Leakage from a river is induced by pumping from the alluvial aquifer when there is excess water available in the river under the prior appropriation doctrine. This water is pumped through pipelines to recharge ponds away from the river. It infiltrates and returns to the river as subsurface flow, augmenting the river flow during critical low-flow, high-demand periods. While the intent of these recharge systems is flow augmentation, subsurface return flows also raise the water table in the alluvium, significantly modifying the hydrology, especially at groundwater-surface water interfaces. Groundwater recharge creates floodplain wetlands and backwater sloughs that serve as waterfowl and aquatic habitat. Managed recharge systems also change the water quality of the alluvium, wetlands, sloughs and river. The objective of this research was to identify the critical hydrologic and water quality variables for a
managed recharge system designed for the multiple benefits of augmenting in-stream flow, while also providing for or enhancing riparian and aquatic habitat. To accomplish the objectives of this study, we combined intensive water quality and quantity monitoring, numerical modeling and a field tracer test at the Tamarack Ranch Recharge Project, near the Colorado-Nebraska State line. The site is complex, consisting of seven high capacity wells, pipelines, recharge ponds, an artificial minnow stream, warming ponds for the minnow stream, and newly-created wetlands and backwater sloughs that are aquatic habitat for minnows-of-concern. Eventually, it is expected that 20 wells will feed up to ten recharge ponds, providing 27,000 acre-feet of additional in-stream flow as part of a three-state agreement to protect critical habitat in Central Nebraska. Water quality was monitored on a regular (monthly or bimonthly) schedule in the alluvium, wetlands, backwater sloughs and river. A tracer study
using SF6 and bromide was used to define hydrologic flow paths, and numerical and analytical modeling determined the hydrologic connections between groundwater and surface water systems. We found that the water quality in the alluvium is slowly being modified to more closely resemble average stream water quality. By using tracers to verify a complex numerical model of the groundwater and surface water, we have developed a defensible model of the effects of pumping and recharge on the alluvium and stream flow return flow hydrograph. Results from this project are already being used to evaluate water rights applications as the junior well owners along the South Platte file augmentation plans with the water courts in Colorado.
Impacts
We have made significant progress in understanding the groundwater/surface water connection in alluvial systems such as that at the Tamarack Ranch Wildlife area, the study site for this project. These methods have applicability to many of the ecosystems in the western U.S.
Publications
- Miller, C.D. and D.S. Durnford. 2005. Modified SDF Semi-analytical Stream Depletion Model in Bounded Alluvial Aquifers. In: Ramirez, J.A. (ed.) Proceedings of the 24nd Annual Geophysical Union Hydrology Days. Fort Collins, CO. p. 86-97.
- Miller, C.D, and D.S. Durnford. 2004. A Review of the SDF Semi-Analytical Stream Depletion Model in Bounded Alluvial Aquifers, Abstract. South Platte Forum, Longmont, Colo., CWRRI Series No. 98, Fort Collins, Colorado.
- Miller, C.D, and D.S. Durnford. 2004. Large-Scale Subsurface Dams in Alluvial Aquifers: Potential for New Water Storage in Colorado? Abstract South Platte Forum, Longmont, Colo., CWRRI Series No. 98, Fort Collins, Colorado.
- Fox, G.A., and D.S. Durnford. 2003. Unsaturated hyporheic zone flow in stream/aquifer conjunctive systems, Advances in Water Resources, 26(9): 989-1000.
- Poceta, J.A., W.E. Sanford, D.L. Harry. 2004. Mapping a Former Channel of the South Platte River within the Tamarack Ranch Wildlife Area Using Electrical Resisitivity, Proceedings of the American Geophysical Union Hydrology Days 2004 Conference, Fort Collins, CO, March 10-13, 2004.
- Poceta, J.A., W.E. Sanford and D.L. Harry. 2004. Electrical resistivity imaging of the Tamarack Ranch State Wildlife Area, northeastern Colorado: Geological Society of America Abstracts with Programs, v. 36, no. 5, p. 506.
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Progress 01/01/03 to 12/31/03
Outputs
This project is ongoing but significant progress has been made this year. First, the model has been completed and calibrated, and it is currently being used to systematically analyze hydrologic and physical options to change the impact of the recharge system on the river and backwater slough hydrology. Second, a student completed analysis of the water quality data for the river, alluvium and sloughs. This data showed a clear impact of the recharge system on water quality in the alluvium. We are continuing to monitor water quality variables on a weekly basis during the pumping season and on a monthly basis in the off season. Third, geophysical seismic tests have been completed and the data is being analyzed. The objective of this component is to identify and map a buried channel and evaluate it's effect on return flows. Lastly, we have completed plans for an SF6 tracer test. This test will begin mid-March 2004.
Impacts
We have made significant progress in understanding the groundwater/surface water connection in alluvial systems such as that at the Tamarack Ranch Wildlife area, the study site for this project. These methods have applicability to many of the ecosystems in the western U.S.
Publications
- Fox, G.A., and D.S. Durnford. 2003. Unsaturated hyporheic zone flow in stream/aquifer conjunctive systems, Advances in Water Resources, 26 (9): 989-1000.
- Fox, Garey A. and D. S. Durnford. 2003. Stream/aquifer analysis tests: estimating streambed and aquifer permeability. Colorado Water 20(3): 5-7.
- Fox, G.A. 2003. Modeling of stream/aquifer interaction during alluvial well depletion. Ph.D. Dissertation, Colorado State University, Fort Collins, CO.
- Durnford, D.S. and Fox, G.A. 2003. Current advances in modeling stream/aquifer interaction. Colorado Water Congress Workshop on Senate Bill 03-073. Longmont, CO, May 22, 2003.
- Fox, G.A. 2003. Estimating streambed and aquifer parameters from a stream/aquifer analysis test. Proceeding of the 23rd Annual Geophysical Union Hydrology Days, J.A. Ramirez (ed) Fort Collins, CO. p. 68-79.
- Fox, G.A. 2003. Improving MODFLOW's RIVER package for unsaturated stream/aquifer flow. Proceedings of the 23rd Annual Geophysical Union Hydrology Days, J.A. Ramirez (ed.) Fort Collins, CO. p. 56-67.
- Watt, J. 2003. Preliminary investigation into the effects of managed recharge on water quality. Proceedings of the 23rd Annual Geophysical Union Hydrology Days, J.A. Ramirez (ed.) Fort Collins, CO.
- Watt, J. 2003. Water quality changes at a stream flow augmentation project, Lower South Platte River, CO. M.S. Thesis, Colorado State University, Fort Collins
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Progress 01/01/02 to 12/31/02
Outputs
A numerical groundwater flow model has been completed in conjunction with the Northern Colorado Water Conservancy District and the Colorado Department of Wildlife. The hydrology of the area and Stream Depletion Factors estimated using this model are similar to results from a previous USGS study. However, we have found significant recycling of the recharge water. The importance of this recycling is under consideration at this time. If water intended for augmentation of the river is instead recycled within the aquifer, the timing of recharge could be significantly delayed. This could have a significant impact on the Platte River Endangered Species Partnership, of which the Tamarack Project is a major contributor. Water quality monitoring is continuing on a biweekly or monthly basis. From these data, it is clear that the presence of the recharge project at Tamarack is altering the water quality of the river and the alluvium. In particular, we show that backwater sloughs
that serve as habitat for endangered species of minnows are variously fed by the groundwater and by the river. In the next year of this project, we will quantify the effects of recharge on water quality more completely. The hydraulic connection between groundwater and surface water is of critical importance in any conjunctive use project. A lower permeability bed, such as often found in the backwater sloughs near the South Platte River, can lead to either saturated or unsaturated flow regimes between the surface water and the underlying aquifer, impacting the in-stream and alluvial hydrology, the riparian ecosystem and assumptions in modeling. We have made significant advances in understanding this connection and have developed a model and field-pumping test to estimate the permeability of the bed. This method has been verified with a field test completed at Tamarack.
Impacts
The current drought in Colorado, as well as a recent court decision that the state engineer's office does not have authority to approve supplemental supply plans, make this project timely and of significant importance to water managers in Colorado and the Western U.S. Further evidence of the importance of this project includes a decision by the National Academy of Science to oversight the Tamarack Recharge Project, the study site for this research. Finally, we have made significant progress in understanding the hydraulic connection between surface and groundwater when there is a low permeability bed layer. This connection is of importance in most groundwater/surface water conjuctive use problems and modeling.
Publications
- Fox, G.A. and D.S. Durnford. 2002. Effect of aquifer parameter uncertainty on analytical estimates of streambed conductance using STRMAQ. In: Ramirez, J.A. (ed.) Proceedings of the 22nd Annual Geophysical Union Hydrology Days. Fort Collins, CO. p. 86-97.
- Fox, G.A., P. DuChateau, and D.S. Durnford. 2002. Analytical model for distributed stream leakage. Ground Water 40(4): 378-384.
- Watt, J., W. Sanford, D. Durnford and J. Stednick. 2002. Hydrogeologic Investigation into the effects of managed recharge on water quality, Lower South Platte River, CO. Paper 102-5, Section T61, Annual Meeting of the Geological Society of America, Denver, CO. October 22-24, 2002.
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Progress 01/01/01 to 12/31/01
Outputs
We are continuing to work closely with Northern Colorado Water Conservancy District (NCWCD) and the Colorado Division of Wildlife (CDOW) to analyze the quantity and quality effects of managed recharge at the Tamarack Ranch Wildlife area. Our research is developing and implementing scientifically based methods for determining the timing, quantity, quality and location of subsurface flow from managed recharge projects. Improved knowledge of these factors will lead to more efficient operation and development of managed recharge, improved augmentation plans and water rights administration, and quantification of the effects of managed recharge on river, alluvium and habitat water quality. In the last year, we have participated in decisions on groundwater modeling (boundary conditions, extent of model area, data input) and calibration, siting decisions for installation of the monitoring wells at the site, initial hydraulic testing and site geologic descriptions. Hydraulic
heads throughout the site are being measured at 34 points in monitoring wells, pumping wells, recharge ponds and at the river. These are measured monthly during the non-pumping periods and twice monthly during pumping periods. Drilling logs for current wells have been examined and included in a database for numerical modeling. The numerical groundwater model has been calibrated using the water level data for steady state conditions. During the summer and fall of 2001, water samples were collected bi-weekly in shallow and deep monitoring wells, two backwater sloughs and the river for water chemistry analysis. Temperature, EC, nitrates, sulfate, dissolved oxygen, specific conductivity, and pH are measured. Although preliminary, these data show significant differences in the water quality and temperature of the river and monitoring wells. Interestingly, one of the backwater sloughs appears similar to the aquifer while the other appears to be similar to the river, indicating differences
in the source water. The analytical models for analyzing the interactions between the aquifer and river are ongoing. We have completed development of an analytical model for aquifer response from pumping near a hydraulically connected stream considering stream partial penetration, well bore storage, well skin effects and the effects of a partially penetrating pumping well in confined and unconfined aquifers. We expect to field-validate the model in the next year. Finally, the methodology for field chemical tracer tests has been developed and these tests will be completed in the spring of 2002. Four graduate students, two in Civil Engineering and two in Earth Resources, have been associated with this project this year.
Impacts
Flow augmentation through managed recharge is expected to increase in importance as rapid growth in the semi-arid west intensifies competition for scarce water resources. It is said that the water in the Platte River in Colorado is used seven times before it reaches the Nebraska border. As this resource and others like it become even more committed, good science is needed to provide water managers the information and tools they will need to use this resource wisely. This project is timely and takes advantage of the opportunity afforded by Tamarack Ranch and the cooperation of the water users and agencies interested in the water quality and water quantity effects of recharge to provide this good science.
Publications
- Fox, G.A. and D.S. Durnford. 2001. Investigation of analytical and numerical models for simulating surface water/groundwater interaction. Proceedings of the 21st Annual Geophysical Union Hydrology Days, April 2-5, Fort Collins, CO.
- Kazbekov, J. 2001. Hydrogeology and Water Chemistry at the Tamarack Recharge Project, Colorado. M.S. Thesis, Colorado State University, Fort Collins, CO.
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Progress 01/01/00 to 12/31/00
Outputs
Managed groundwater recharge is an effective and affordable form of conjunctive water management in the western United States. The primary intent of managed recharge is to re-regulate flows, enabling junior groundwater appropriators to withdraw water from tributary alluvial aquifers without harming existing senior water rights holders. Water is diverted from the river during high flow periods and delivered to recharge ponds where it is allowed to infiltrate and return as subsurface flow to the river. The timing of the return flow, and hence the benefit, is a result of selecting the best locations of the recharge basins with respect to their distances from the river. This project uses the Tamarack Recharge Project at the Tamarack Ranch Wildlife Area as a study site. The Tamarack Project is a complex hydrogeologic and ecological system, comprised of well fields, pipelines, wetlands, artificial and natural sloughs for fish habitat, and streams. The Tamarack Project is
Colorado's contribution to the Platte River Recovery Program, an agreement with Wyoming, Nebraska and the Department of Interior to protect the habitat of endangered cranes in Nebraska. Colorado's contribution includes 27,000 acre-feet of additional annual flow in the South Platte River, primarily from managed recharge at Tamarack. The specific objective of this project is to apply advanced field geophysical studies, well data, tracer tests and numerical modeling to determine the timing, quantity and location of recharge to the South Platte River at the Tamarack Ranch Wildlife Area. We are working closely with researchers in the Earth Resources Department, the Colorado Department of Wildlife and Northern Colorado Water Conservancy District to model the hydrology at the Tamarack Recharge Project. Three graduate students are also now working on this project. One is a Ph.D. USDA National Needs Fellow. The other two are M.S. students. This year, we have made significant progress toward
our goal. Water tables are being monitored at least monthly, the bedrock and water table contours at the site have been mapped and preliminary analytical modeling is complete. We have also completed the first phase of the field geophysical investigation, performed and analyzed aquifer test data and analyzed aquifer tests done previously at the site by other research groups. Tracer test design is ongoing and we are currently selecting the tracers that will be used. The field injections will be staged. It is anticipated that at least three tracers will be injected: bromide, fluoride and SF6. Numerical modeling of the site is ongoing.
Impacts
In the South Platte, recharge programs are an increasingly important source of augmentation water; increasing from 20,000 acre-feet in 1980 to 117,000 acre-feet in 2000. As water use on the front range continues to increase, the South Platte will be further stressed. Understanding managed groundwater recharge projects in the South Platte River Basin is essential to future protection of the groundwater supplies and return flows upon which irrigated agriculture depends. In addition, Colorado has committed to augmenting river flows in the lower South Platte by 27,000 acre-feet annually in an agreement with Nebraska, Wyoming and the Department of Interior. It is critical that Colorado be able to demonstrate that they are meeting this committment. Our research will develop and implement scientifically based methods for determining the timing, quantity and location of subsurface flow from managed recharge projects. Improved knowledge of these factors will lead to (i) more
efficient operation and development of managed recharge, (ii) improved augmentation plans and water rights administration and (iii) a defensible estimate of Colorado's contribution to the Platte River Recovery Program.
Publications
- No publications reported this period
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Progress 01/01/99 to 12/31/99
Outputs
Water resource management organizations are facing the challenge of simultaneously protecting and restoring aquatic habitat, satisfying new legal obligations under the Endangered Species Act to increase in-stream flows, while continuing to meet existing water demands. We are working closely with the Colorado Department of Wildlife and the Northern Colorado Water Conservancy District to model the hydrology at the Tamarack Recharge Project located on the South Platte River in northeast Colorado. The Tamarack Project is a managed recharge project that is a complex hydrogeologic and ecological system, comprised of well fields, pipelines, wetlands, artificial and natural sloughs, and streams. This year, we completed a hydrologic field investigation including aquifer testing, gravity meter surveys, seismic surveys and surface mapping using GPS. From this data, we obtained spatial information on the depth to bedrock, depth to water table, hydraulic conductivities and surface
elevations. These data were entered into a groundwater model, MODFLOW, and the model was calibrated for the site. We are currently designing a field tracer test which we expect to complete next summer. The results of the tracer test will be used to verify the model. Once the model is calibrated and verified, we will use it to evaluate feasible design options and their impacts on the aquatic habitat at the site.
Impacts
This project is significant because Tamarack, the field site chosen for this study, provides a unique opportunity for a landmark study of a complex multi-objective watershed management project. It is also particularly important to the State of Colorado because Tamarack is the cornerstone of Colorado's contribution to a Cooperative Agreement entered into by Colorado, Nebraska, Wyoming and the Dept. of the Interior on 7/1/97.
Publications
- Shrier, C.J., D. Durnford, and J. Altenhofen. 1999. The development of a multi-criteria managed groundwater recharge facility to augment instream flows and restore protected species habitat. Proc. Watershed Management to Protect Delining Species. American Water Resources Association. Herndon, VA.
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Progress 07/01/98 to 12/31/98
Outputs
A critical problem facing Colorado and the Western U.S. is the intensifying competition for water by expanding urban centers, agriculture and in-stream environmental and wildlife habitat concerns. Confronted with this increased competition, development of groundwater resources will likely increase rapidly as water managers search for ways to meet the expanding and often-conflicting demands. Underground storage, artificial recharge and recovery systems (ASR), and recharge ponds are all extremely promising alternatives for overcoming short-term, seasonal, or long-term differences between water supply and demand. In the initial stage of this research, we have concentrated on aquifer storage and recovery (ASR) systems and their use in Colorado. In 1983, Congress authorized the U.S. Department of Interior Bureau of Reclamation's High Plains Ground Water Recharge Demonstration Program to evaluate recharge, storage and recovery opportunities. Interior selected 21 projects,
thirteen of which reached the construction stage. As of the end of 1994, 20 ASR projects were operational in the U.S., compared to three in 1983. About 40 additional projects are currently in various stages of investigation, design, permitting, construction, testing or operational startup. As an initial part of this project, we are reviewing the technical efficacy, economic efficiency and financial feasibility of these projects, particularly those in Colorado. We are also exploring the feasibility of using water quality changes during recharge as part of a water treatment process and a method of estimating recovery well clogging. Recharge opportunities offer a practical and promising alternative for the storage of vast amounts of water, as traditional surface water storage facilities become harder and harder to get approved and constructed. Whereas widespread opportunities exist for recharge and conjunctive use of water in both urban and agricultural areas, progress is slow and
municipalities, in particular, are hesitant to fully disclose all aspects of future water supply plans. Thus, in order to gather as much current information as possible, we have met with contractors, lawyers, engineers and water district managers to ascertain the state of acceptance of this technology in Colorado. The future of ASR technology appears bright. The objectives of almost all existing ASR applications in the U.S. are seasonal, long-term or emergency storage of drinking water. However, many other applications are being considered. Of relevance to Colorado, these include restoration of groundwater levels, nutrient reduction in agricultural runoff, deferral of water treatment facilities expansion, and timely supply of water for agriculture or to meet interstate compacts.
Impacts
(N/A)
Publications
- No publications reported this period
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