WATER TRANSFERS AND THEIR IMPACTS: LESSONS FROM THREE COLORADO WATER MARKETS1

ABSTRACT: This paper presents an analysis of the effects of different institutional arrangements and economic environments on water markets. Characteristics of water rights transfers in the South Platte Basin of Colorado and transfers of shares of the Northern Colorado Water Conservancy District (NCWCD) are compared to show how different institutional arrangements can affect the types and size distributions of transfers. The characteristics of water rights transfers in the prosperous South Platte are then compared with water rights transfer characteristics in the economically marginal Arkansas River basin of Colorado to identify the effects of different economic environments. Finally, the economic losses from reductions in irrigated acreage resulting from water transfers are estimated for the South Platte and Arkansas and compared with purchase prices by municipalities. Transfers in the South Platte were to new uses in the same basin, while more recent transfers in the Arkansas were to out of basin users. Transfers of South Platte rights and especially NCWCD shares were small and continuous over time, while transfers in the Arkansas were dominated by a few very large transfers. The negative impacts are judged to be more severe in the Arkansas basin than in the South Platte. Purchase prices paid by municipalities substantially exceeded capitalized transitional losses in the selling areas. In the South Platte, gains and losses were in the same basin, while the Arkansas absorbed the losses, with the benefits going to the purchasing basin.     

Estimating Crop Water Use via Remote Sensing Techniques vs. Conventional Methods in the South Platte River Basin,Colorado

We compared two methods of estimating crop water consumption to assess whether remote sensing techniques provide consumptive use (CU) estimates commensurate with conventional methods. Using available historical satellite and meteorological data, we applied Mapping EvapoTranspiration at high Resolution using Internalized Calibration (METRIC) to 317,455 ha in the South Platte basin, in northeastern Colorado, for the 2001 irrigation season. We then compared these derived CU estimates with values calculated by using the Colorado Water Conservation Board's South Platte Decision Support System StateCU model. Evaluating the data by irrigation ditch service area, we disaggregated the output to allow for comparison by service area size, crop type, irrigation method, water supply source, and water availability. We concluded that METRIC is a suitable alternative to StateCU in the South Platte basin and could help to identify areas with inhibited crop growth or deficit irrigation practices. In addition, METRIC could be used as a complement to StateCU to refine StateCU model parameters, allowing for more accurate estimates of crop water shortages and groundwater recharge associated with irrigation delivery and application.     

DROUGHT EFFECTS ON WATER QUALITY IN THE SOUTH PLATTE RIVER BASIN,COLORADO1

ABSTRACT: Twenty‐three stream sites representing a range of forested, agricultural, and urban land uses were sampled in the South Platte River Basin of Colorado from July through September 2002 to characterize water quality during drought conditions. With a few exceptions, dissolved ammonia, Kjeldahl nitrogen, total phosphorus, and dissolved orthophosphate concentrations were similar to seasonal historical levels in all land use areas during the drought. At some agricultural sites, decreased dilution of irrigation return flow may have contributed to higher concentrations of some nutrient species, increased primary productivity, and higher dissolved oxygen concentrations. At some urban sites, decreased dilution of base flow and wastewater treatment plant effluent may have contributed to higher dissolved nitrite‐plus‐nitrate concentrations, increased primary productivity, and higher dissolved oxygen concentrations. Total pesticide concentrations in urban and agricultural areas were not consistently higher or lower during the drought. At most forested sites, decreased dilution of ground water‐derived calcium bicarbonate type base flow likely led to elevated pH and specific‐conductance values. Water temperatures at many of the forested sites also were higher, contributing to lower dissolved oxygen concentrations during the drought.     

IMPACTS OF WATER USE EFFICIENCY ON ENERGY DEVELOPMENT1

ABSTRACT: To help meet national energy demands, interest has been focused on the coal, oil shale, and uranium deposits of the Upper Colorado River Basin. Several energy output projections for the basin have been presented based upon water availability. Inherent in all these analyses are estimates as to the rate of water use in each energy development. New energy technologies are characterized by parameters extrapolated from small scale energy facilities. The data provide projected costs, conversion efficiencies, and material inputs and outputs. Alternative techniques for process cooling and solids handling provide variable rates of water use which affect other conversion parameters. Results from a mathematical model are used in analyzing the sensitivity of an optimal energy development strategy for the Upper Colorado River Basin. The impacts of alternative water use rates are investigated in terms of net energy output, total cost, and displacements in the development strategy. Similarly, controls and regulations on energy resource development are evaluated.     

NUTRIENT CONCENTRATIONS IN WASTEWATER TREATMENT PLANT EFFLUENTS,SOUTH PLATTE RWER BASIN1

ABSTRACT: Accurate data about nutrient concentrations in wastewater treatment plant effluents are needed for river basin water-quality studies. As part of the U.S. Geological Survey's National Water-Quality Assessment Program in the South Platte River Basin, nutrient data were requested from 31 wastewater-treatment plants located in the basin. This article describes the types of nutrient data available from the plants, examines the variability of effluent nutrient concentrations, and discusses methods for estimation of nutrient concentrations where data are lacking. Ammonia was monitored at 88 percent of the plants, nitrite plus nitrate was monitored at 40 percent of the plants, and organic nitrogen and phosphorus were monitored at less than 25 percent of the plants. Median total nitrogen concentrations and median total phosphorus concentrations were small compared to typical literature estimates for wastewater-treatment plants with secondary treatment. Nutrient concentrations in effluent from wastewater-treatment plants varied widely between and within plants. For example, ammonia concentrations varied as much as 5 mg/L during a day, as much as 10 mg/L from day to day, and as much as 30 mg/L from summer to winter within a plant. In the South Platte River Basin, estimates of median annual ammonia and nitrite plus nitrate concentrations can be improved based on plant processes; and nitrite plus nitrate and organic nitrogen concentrations can be estimated based on ammonia concentrations. However, to avoid large estimation errors, more complete nutrient data from wastewater-treatment plants are needed for integration into river basin water quality studies. The paucity of data hinders attempts to evaluate the relative importance of point source and nonpoint source nutrient loadings to rivers.     

GROUND WATER AS A SOURCE OF NUTRIENTS AND ATRAZINE TO STREAMS IN THE SOUTH PLATTE RIVER BASIN1

ABSTRACT: Concentrations of nitrite plus nitrate, ammonia, orthophosphate, and atrazine were measured in streams and ground water beneath the streams at 23 sites in the South Platte River basin of Colorado, Nebraska, and Wyoming to assess: (1) the role of ground water as a source of nutrients and atrazine to streams in the basin, and (2) the effect of land-use setting on this process. Concentrations of nitrite plus nitrate, ammonia, orthophosphate, and atrazine were higher in ground water than in the overlying streams at 2, 12, 12, and 3 of 19 sites, respectively, where there was not a measurable hydraulic gradient directed from the stream to the ground water. Orthophosphate was the only constituent that had a significantly higher (p ≤ 0.05) concentration in ground water than in surface water for a given land-use setting (range land). Redox conditions in ground water were more important than land-use setting in influencing whether ground water was a source of elevated nitrite plus nitrate concentrations to streams in the basin. The ratios of nitrite plus nitrate in ground water/surface were were significantly lower (p ≤ 0.05) at sites having concentrations of dissolved oxygen in ground water ≤ 0.5 mg/L than at sites having dissolved oxygen concentrations ≥ 0.5 mg/L. Elevated concentrations of ammonia or atrazine in ground water occurred at sites in close proximity to likely sources of ammonia or atrazine, regardless of land-use setting. These results indicate that land-use setting is not the only factor that influences whether ground water is a source of elevated nutrient and atrazine concentrations to streams in the South Platte River Basin.     

IMPACTS OF A SEVERE SUSTAINED DROUGHT ON COLORADO RWER WATER RESOURCES1

ABSTRACT: The impacts of a severe sustained drought on Colorado River system water resources were investigated by simulating the physical and institutional constraints within the Colorado River Basin and testing the response of the system to different hydrologic scenarios. Simulations using Hydrosphere's Colorado River Model compared a 38-year severe sustained drought derived from 500 years of reconstructed streamflows for the Colorado River basin with a 38-year streamflow trace extracted from the recent historic record. The impacts of the severe drought on streamflows, water allocation, storage, hydropower generation, and salinity were assessed. Estimated deliveries to consumptive uses in the Upper Basin states of Colorado, Utah, Wyoming, New Mexico, and northern Arizona were heavily affected by the severe drought, while the Lower Basin states of California, Nevada, and Arizona suffered only slight shortages. Upper Basin reservoirs and streamflows were also more heavily affected than those in the Lower Basin by the severe drought. System-wide, total hydropower generation was 84 percent less in the drought scenario than in the historical stream-flow scenario. Annual, flow-weighted salinity below Lake Mead exceeded 1200 ppm for six years during the deepest portion of the severe drought. The salinity levels in the historical hydrology scenario never exceeded 1100 ppm.     

ALTERNATIVES FOR SALINITY MANAGEMENT IN THE COLORADO RIVER BASIN1

ABSTRACT The Colorado River Basin faces the dilemma of an increasing demand for water while presently struggling with salinity concentrations approaching critical levels for some water uses. Based upon projected development salinity concentrations are predicted to exceed 1200 mg/1 at Imperial Dam by the year 2010. Annual losses to the basin economy associated with increased salinity will exceed $50 million by the year 2010. Although methods of controlling salt discharges are relatively unrefined, certain conclusions, based upon Bayesian statistical methods, can be reached. Five basic alternatives for coping with the problem are presented and evaluated in this paper: (1) do nothing; (2) adopt arbitrary salinity standards; (3) limit development; (4) control salt discharges at a cost equal to the cost of doing nothing, or (5) minimize total costs to the basin. Total costs associated with any given alternative, or the given salinity resulting, are the sum of salinity detriments (cost to users for water of increased salinity plus economic multiplier effects) plus the cost of constructing salt discharge control works. These impacts upon basin economy and Colorado River water quality for each alternative are presented and related to questions of equity which will play a role in arriving at any long-term solution to the Basin's problem.     

A DIGITAL MODEL APPLIED TO GROUND WATER RECHARGE AND MANAGEMENT1

ABSTRACT: Under Colorado's appropriative water right system, withdrawals by junior ground water rights must be curtailed to protect senior surface water appropriators sharing the same river system unless the ground water users replace the amount of their injury to the river under an approved plan for augmentation. Compensation of such injury with surface water may not only be expensive but unreliable in dry years. As an alternative, the curtailment of pumping may be obviated by recharging unused surface water into the aquifer when available and withdrawing it when needed. In order to manage such an operation, a practical tool is required to accurately determine that portion of the recharge water that does not return to the river before pumping for irrigation. A digital model was used for this purpose in a demonstration recharge project located in the South Platte River basin in northeastern Colorado. This paper summarizes the experiences gained from this project, the results of the digital model, the economic value of recharge, and the feasibility of the operation. It was determined through the use of the digital model that, with the given conditions in the area, 77 percent of the recharged water remained available for pumping. Economic analyses showed that water could be recharged inexpensively averaging about two dollars per acre foot.     

PEAK PERIOD DESIGN STANDARDS FOR SMALL WESTERN U.S. WATER SUPPLY SYSTEMS1

ABSTRACT: In order to determine design capacities for various components of municipal and rural domestic water supply systems, engineers must estimate water requirements for an entire year (water rights), for the peak season (reservoir storage), for the peak day (pump or treatment plant size), and for peak hour (pipeline sizes). Historically, per capita water use rates have varied greatly between systems, particularly in semiarid regions where outdoor demands are large. The resulting uncertainty in design capacity estimates can cause either inadequate capacities or premature investment. In order to minimize that uncertainty multiple regression and frequency analyses were made of the various water demand parameters mentioned above for 14 systems in Utah and Colorado. Specifically, demand functions are reported for average month, peak month, and peak day. Peak hour demands were also studied but are reported in a different paper. The independent variables which were significant for monthly and daily demands were price of water and an outdoor use index which includes the effect of variation in landscaped area and accounts for use of supplementary ditch or pressure irrigation systems. The demand functions were developed with data from systems varying in size from very small low density rural systems to Salt Lake City's water system. The correlation coefficients (R²) vary from 0.80 to 0.95.     

TREE-RING RECONSTRUCTION OF UPPER GILA RWER DISCHARGE1

ABSTRACT: Effective planning for use of water resources requires accurate information on hydrologic variability induced by climatic fluctuations. Tree-ring analysis is one method of extending our knowledge of hydrologic variability beyond the relatively short period covered by gaged streamflow records. In this paper, a network of recently developed tree-ring chronologies is used to reconstruct annual river discharge in the upper Gila River drainage in southeastern Arizona and southwestern Arizona since A.D. 1663. The need for data on hydrologic variability for this semi-arid basin is accentuated because water supply is inadequate to meet current demand. A reconstruction based on multiple linear regression (R²=0.66) indicates that 20th century is unusual for clustering of high-discharge years (early 1900s), severity of multiyear drought (1950s), and amplification of low-frequency discharge variations. Periods of low discharge recur at irregular intervals averaging about 20 years. Comparison with other tree-ring reconstructions shows that these low-flow periods are synchronous from the Gila Basin to the southern part of the Upper Colorado River Basin.     

Conservation Opportunities for Securing In-Stream Flows in the Platte River Basin: A Case Study Drawing on Casper,Wyoming’s MunicipalWater Strategy

The Platte River Basin consists of tributaries largely in Wyoming, Colorado and Western Nebraska, with the main stem in Central Nebraska. Critical wildlife habitat on the main stem requires additional in-stream flows. The watershed is one hosting multiple resources, a variety of users, and managed by an array of state and federal agencies. This study proposes a basis for securing in-stream flows for the Platte River. Candidate water supply mechanisms are suggested based on the way in which Casper, Wyoming secured water for its municipal needs. Canal lining is compared to a dam project, increasing reservoir storage, and purchasing water rights, with consideration also made for water pricing to reduce municipal use. Comparisons are based on economic efficiency, potential water conservation, and property rights criteria. Canal lining, coupled with demand management, is shown to conserve water best, given the set of efficiency and cost criteria for in-stream flow enhancement. The approach offers an opportunity to organize the water supply choice context in a transboundary watershed when quantitative information is limited.     

THE IMPACT OF STOCKWATERING PONDS (STOCKPONDS) ON RUNOFF FROM LARGE ARIZONA WATERSHEDS1

ABSTRACT: Major water rights adjudications involving the Little Colorado River Basin and Gila River Basin are presently underway within Arizona. Water resource managers are faced with the prospect of evaluating and regulating tens of thousands of water diversions and uses. Stockponds comprise a large percentage of the total number of water diversions within these basins. Water balance studies conducted on the Little Colorado River watershed above Lyman Lake and on the Gila River watershed above Solomon, Arizona, indicate that the impact of stockponds on the water available to downstream users is insignificant when compared to total watershed production. Considering that there are an estimated 25,000 stockponds in the Gila River basin alone, rigorous case-by-case investigations and stringent regulation of individual stockponds may be impractical and unwarranted. Therefore, stock-pond claims within the context of the general adjudication process may be effectively handled by partial summary judgment, thereby allowing the court to concentrate on major water users and water rights issues.     

SALT TRANSPORT BY THE SOUTH PLATTE RIVER IN NORTHEAST COLORADO1

ABSTRACT: The salinity of the lower South Platte River in Colorado is characterized by plotting the average annual flow, total dissolved solids, and salt mass flow against distance along the stream. The plots show that salts are being leached from the irrigated lands above Greeley and are being deposited on the irrigated lands below Greeley. The salt deposition on the lower lands will result in their salination. The plots show also that fall and winter stream flows carry most of the salt loads. These fall and winter flows are stored in off stream reservoirs for use during the irrigation season. Therefore these salts are transferred to the lower irrigated lands where they accumulate. The salt balance for these lands can be improved by permitting the fall and winter flows to leave the basin, or by providing adequate land drainage coupled with supplemental irrigation water.     

Hydrologic Sensitivity to Climate and Land Use Changes in the Santiam River Basin,Oregon

Future changes in water supply are likely to vary across catchments due to a river basin's sensitivity to climate and land use changes. In the Santiam River Basin (SRB), Oregon, we examined the role elevation, intensity of water demands, and apparent intensity of groundwater interactions, as characteristics that influence sensitivity to climate and land use changes, on the future availability of water resources. In the context of water scarcity, we compared the relative impacts of changes in water supply resulting from climate and land use changes to the impacts of spatially distributed but steady water demand. Results highlight how seasonal runoff responses to climate and land use changes vary across subbasins with differences in hydrogeology, land use, and elevation. Across the entire SRB, water demand exerts the strongest influence on basin sensitivity to water scarcity, regardless of hydrogeology, with the highest demand located in the lower reaches dominated by agricultural and urban land uses. Results also indicate that our catchment with mixed rain‐snow hydrology and with mixed surface‐groundwater may be more sensitive to climate and land use changes, relative to the catchment with snowmelt‐dominated runoff and substantial groundwater interactions. Results highlight the importance of evaluating basin sensitivity to change in planning for planning water resources storage and allocation across basins in variable hydrogeologic settings.     

Residential Water Demand Management: Lessons from Aurora,Colorado1

Abstract: Residential water demand is a function of several factors, some of which are within the control of water utilities (e.g., price, water restrictions, rebate programs) and some of which are not (e.g., climate and weather, demographic characteristics). In this study of Aurora, Colorado, factors influencing residential water demand are reviewed during a turbulent drought period (2000‐2005). Findings expand the understanding of residential demand in at least three salient ways: first, by documenting that pricing and outdoor water restriction policies interact with each other ensuring that total water savings are not additive of each program operating independently; second, by showing that the effectiveness of pricing and restrictions policies varies among different classes of customers (i.e., low, middle, and high volume water users) and between predrought and drought periods; and third, in demonstrating that real‐time information about consumptive use (via the Water Smart Reader) helps customers reach water‐use targets.     

Price Determination and Efficiency in the Market for South Platte Basin Ditch Company Shares

Water scarcity presents an obstacle to economic development in the western United States. Water rights markets help improve water allocation, allowing states to derive the highest economic benefit from available resources, and supporting new uses and economic development. However, the implicit (marginal) prices of water rights attributes are uncertain. To address this problem, we apply econometric analysis to a unique dataset to estimate the implicit values that market participants place on the attributes of shares of ditch company water rights in Colorado's South Platte River Basin. Our analysis demonstrates that ditch company share buyers value proximity of water diversion, reliability of water deliveries, and temporal flexibility of water use. To assess reliability we introduce the use of the coefficient of variation to capture, in one variable, the randomness of supply from ditch company shares that are not a single water right, but a portfolio of rights with different appropriation dates. Finally, we test and correct for spatial autocorrelation for the first time in a study of water market prices.     

Evaluation of the Temporal Transferability of a Model Describing Dissolved Solids in Streams of the Upper Colorado River Basin1

Kenney, Terry A. and Susan G. Buto, 2012. Evaluation of the Temporal Transferability of a Model Describing Dissolved Solids in Streams of the Upper Colorado River Basin. Journal of the American Water Resources Association (JAWRA) 48(5): 1041‐1053. DOI: 10.1111/j.1752‐1688.2012.00667.x Abstract: The application of a nonlinear least‐squares regression model describing the sources and transport of dissolved solids in streams of the Upper Colorado River Basin, and that was calibrated using data from water year 1991, was evaluated for use in predicting annual dissolved‐solids loads for the years 1974 through 1998. Simulations for each water year were run using annual climate data. To evaluate how well the model captures the observed annual variability across the basin, differences in predicted annual dissolved‐solids loads for each simulated year and 1991 were compared with differences in monitored annual loads. The temporal trend of the differences between predicted annual loads for the simulated years and the load for 1991 generally followed the trend of the monitored loads. The model appears to underpredict the largest annual loads and overpredict some of the smaller annual loads. An underprediction bias for wetter years was evident in the residuals as was an overprediction bias, to a lesser degree, for drier years. A regression analysis on the residuals suggests that the underprediction bias is associated with precipitation differences from 1991 and with previously defined downward trends in dissolved‐solids concentrations in the basin. In general, given the representative climatic conditions, the model adequately performs throughout the period examined. However, the model is most transferable to years with climatic conditions similar to 1991.     

Impacts of Bakken Shale Oil Development on Regional Water Uses and Supply

The Bakken shale play in western North Dakota is one of the largest unconventional oilfields in the United States, but published research about impacts on the region's water resources is rare. In this study, besides examining North Dakota water management policies and activities, we also analyzed three datasets: the Bakken horizontal well completion data (2008‐2014), North Dakota permitted water consumption data (2000‐2014), and groundwater level and streamflow observations in western North Dakota (2000‐2014). We found from 2008 to 2014, the annual total industrial water uses for Bakken shale oil development ranged between 0.5 and 10% of statewide total consumptive water use. The percentage increases were between 3.0 and 40% within the Bakken oil production region. The increased population of temporary oilfield service workers contributed additional domestic water use, which was equivalent to ~15% of annual industrial water use for the shale oil development in the Bakken. Despite being in a semiarid region, the impact of Bakken development on regional water supply was limited because the water in the Bakken was adaptively managed and the region received on average over 20% more precipitation than normal during 2008‐2014. Of the 15 glaciofluvial aquifers under study, 12 have seen water levels increasing or unchanged and the water levels for the remaining 3 aquifers have decreased.