2006

Brackish Groundwater Desalination: Innovation and Opportunities for Successful and Economical Project Implementation

Joseph W. Norris — Tue, 24 Mar 2009 11:21:34 PDT

Recent growth in demand for alternative water resources in South Texas has resulted in a rapid growth of brackish groundwater desalination plants, including the largest in Texas. This paper will focus on the successes and lessons learned from Southmost Regional Water Authority Desalination Plant and other projects completed or underway in the area. By completing regional projects by construction management methods, Owners are realizing proven savings and development of projects faster than conventional methods of construction. Projects completed and under construction have save the owner as much as 30% in costs and 50% in timesaving. Only local funds were used to achieve these savings.

Economic Implications of Desalination in South Texas

Allen W. Sturdivant et al. — Tue, 24 Mar 2009 11:16:18 PDT

Desalination offers an opportunity for source diversification of water for many communities, along with possible defenses against security threats potentially affecting clean water supplies. The economic costs associated with constructing and operating desalination plants in South Texas are investigated. Primary data utilized in the analysis include engineering considerations and actual costs associated with existing and plants under construction in South Texas. Specific costs considered include raw water acquisition and transport, pretreatment, and purification. Sensitivity parameters include source and quality of raw water, energy costs, size of plant, and other heuristic aspects of plant design and development. Annuity equivalent costs are reported on a per ac-ft of finished water basis, f.o.b. desalination plant.

Advanced Concepts in Desalination

Thomas M. Mayer et al. — Tue, 24 Mar 2009 11:08:04 PDT

The Advanced Concepts Desalination program at Sandia National Laboratories aims to increase the availability of fresh water through cost-effective developments in desalination technology, particularly for treatment of brackish ground water. The major obstacles to widespread implementation of desalination are the high energy consumption of current reverse osmosis (RO) technology, low recovery due to concentration of low solubility salts, and the limited options for concentrate disposal. In this talk we review a number of efforts initiated by Sandia to address these problems. Near-term projects focus on increasing fresh water recovery and concentrate management. An innovative hybrid RO-electrodialysis system isolates and removes sparingly soluble calcium salts from an RO concentrate stream, allowing recycling of the concentrate and additional water recovery. A similar concept uses an inter-stage precipitator to remove slightly soluble salts prior to additional RO treatment. Where deep well injection is the preferred method of concentrate disposal, geochemical modeling is being used to evaluate the compatibility and chemical stability of the concentrate with the disposal reservoir. Long-range R&D programs include development of high-efficiency nanostructured membranes for RO and electrodialysis that may substantially decrease the energy requirements for production of fresh water. New concepts in membrane module construction are being examined to make the best use of high efficiency membranes. New treatments for preventing and controlling membrane biofouling will increase the efficiency and lower the cost of operation of membrane processes.

Modeling of Desalination Concentrate Storage Options for Future Recovery and Use

Charles D. Turner et al. — Tue, 24 Mar 2009 11:03:04 PDT

Ciudad Juárez, Chihuahua, a rapidly growing city across the Rio Grande from El Paso, Texas with a 2005 population in excess of 1.2 million, relies exclusively on ground water from an aquifer known as the Hueco Bolson. The aquifer’s fresh water is being depleted and it is degrading in quality due to the lateral inflow of brackish water. Although the Hueco Bolson’s fresh water is diminishing, it still contains a considerable quantity of brackish water. This paper defines the feasibility of using desalination technology in conjunction with concentrate storage to extend the ‘life’ of the Juárez portion of the Hueco Bolson. Well injection of the concentrate was analyzed based on the premise that the cones of depression created by well pumping could provide a storage area for the concentrate. So doing would enable the brackish concentrate to be ‘stored’ for future use when advances in desalination technology will render the stored concentrate into an economically recoverable resource , unlike evaporation ponds that result in the permanent loss of water due to vaporization. The research team used a combination of three software systems for this portion of the analysis: a ground water modeling software, a mass transport extension to the ground water modeling software, and GIS software to facilitate the visualization of model outputs. The technical report on which this paper is based was authored by Turner and Hamlyn (2004).

Water Quality Considerations for the Agricultural and Urban Use of Reclaimed Water in the Southwest

George Di Giovanni et al. — Tue, 24 Mar 2009 10:59:03 PDT

Reclaimed water use has the potential to help communities, especially in the arid southwest, meet growing water demands under dwindling fresh water supplies. Reclaimed water represents a reliable supply of water for small-scale production agriculture, urban landscape use, industrial use and groundwater recharge. However, the chemical and microbiological quality of reclaimed water needs to be considered. This panel session will describe field and laboratory experiences with reclaimed water and identification of some of the chemical and microbiological issues that need to be addressed for successful and safe application.

Appraising Salinity Hazard to Landscape Plants and Soils Irrigated with Moderately Saline Water

Seichii Miyamoto — Tue, 24 Mar 2009 10:54:11 PDT

Water planners and managers are faced with the increasing needs to utilize nonpotable water for irrigating urban landscapes in water-shortage areas of the arid West. However, existing guidelines for assessing suitability of water for irrigation is rather broad. This paper presents updated guidelines based on the experience in west Texas and southern New Mexico where water of relatively high salinity is used for landscape irrigation.

Salinity Effects and Salt Movement from Surface Applied Gray Water and Brackish Water

Zhuping Sheng et al. — Tue, 24 Mar 2009 10:49:17 PDT

In this paper authors present results of a soil column experiment on salinity effects and salt movement from surface applied gray water and brackish water.

Rainwater Harvesting for Enhanced Groundwater Recharge Through Capture of Increased Runoff from Site Development

Mark Miller — Tue, 24 Mar 2009 10:45:10 PDT

In many parts of the western U.S. that rely on groundwater, the sustainability of aquifers is tenuous. Water supply managers have opportunities for rainwater harvesting where community development increases stormwater runoff. Stormwater control systems that increase groundwater recharge can offset the continually increasing water demands experienced in many communities.

The Potential of Water Saving and Water Capturing Innovations in Albuquerque Single Family Homes

Andrew Funk — Tue, 24 Mar 2009 10:42:14 PDT

The need for innovative water saving and water capturing strategies in Albuquerque single family homes (SFH) is evident by the city’s vulnerability to drought, climate change and population growth. The intrinsic value of modern innovations is that they offer the potential to produce the largest, most cost effective and environmentally sound alternative source of water required to meet future demand. Moreover, recognizing the intimate relationship between water use and the energy consumed in conveyance, treatment, end uses and waste treatment, allows policy makers to meet water and energy use reduction goals simultaneously.

Rainwater Harvesting Education in Texas

Billy Kniffen — Tue, 24 Mar 2009 10:38:15 PDT

Rainwater harvesting is fast becoming an optional source of water for homes, landscape and wildlife. Rainwater has been growing in popularity in the Texas Hill Country for homes by reducing demand on municipal water supplies and water wells and providing opportunities to build homes with no other source of water. The first known Master Gardener Specialist program in Rainwater Harvesting will be held in Menard, Texas and hosted by Texas Cooperative Extension and myself in June 2006. Demonstration models have been installed in 7 different counties at public schools in Central and West Texas with my assistance. My house is totally on rainwater and collected data shows we use 35 gallons of water per person a day in our home and have the ability to maintain our home on less than 9 inches of rainfall per year. I serve on the America Rainwater Capture Systems Association board as the Central United States representative, I have assisted with several publications including Harvesting Rainwater For Wildlife to be out in January 2006, Rainwater Harvesting an Extension booklet published in August 2004 and Rainwater Harvesting in West Texas. I have given presentations on the basics of rainwater harvesting throughout Texas and serve on Extensions Rainwater Task Force. I would like to provide information on the Master Gardener Specialist Program, provide data from my home and educational efforts of Texas Cooperative Extension and other governmental agencies.

An Examination of the Legal Issues in Municipal Water Reuse

Ronald A. Kaiser — Tue, 24 Mar 2009 10:34:04 PDT

Fiscal, physical, environmental and political consideration have severally restricted building new reservoirs to meet municipal water needs in Texas and throughout the American west. Water management is transitioning from an era of reservoir construction to one of more intensive management through conservation, reallocation, desalination, rainwater harvesting, aquifer storage and recovery and reusing treated effluent as means of meeting water supply needs. As opportunities for conventional water supply development dwindle and costs for wastewater treatment and disposal climb, the role water reuse plays in water resource management increases significantly. Both nonpotable and potable applications of reclaimed water offer a means to extend and maximize the utility of limited water resources. Increasing biological and microbiological knowledge, improved wastewater treatment technology, and strict legal requirements on the quality of discharged effluent have elevated the notion of wastewater reuse to a realistic water supply alternative.

Salinization of a Desert Reservoir? Inflows, Solutes, and Mixing in Lake Amistad

Alan W. Groeger et al. — Tue, 24 Mar 2009 10:15:53 PDT

Three rivers of very different physical and chemical nature (the Rio Grande/Rio Bravo, Pecos, and Devils) flow into the international reservoir Lake Amistad. This reservoir is a very valuable water supply for downstream and local agricultural and domestic interests, and has a huge upstream drainage (323,643 km2), which includes rivers draining both the western and eastern slopes of the southern Rockies, and a large proportion of the Chihuahuan Desert, including the Rio Conchos in Mexico. In 2004 a great deal of the volume of the reservoir, which had decreased dramatically since 1994 during an extended drought, has been recovered through high inflows. Because of increasing intensive agricultural use of irrigation waters upstream, projections have been made that the Rio Grande and L. Amistad waters will become more salty--to a point to that would significantly decrease the value of the water for downstream human uses. Our data (2004-2006) and historical sources suggests that there are a number of complex mechanisms, including the mixing of the rivers into the reservoir, seasonal inflow patterns, local groundwaters, chemical processes and reservoir releases which have ameliorated upstream salinization at Amistad.

Simulation of Impacts of Water Availability and Weather Conditions on Management Plan for Amistad Reservoir

Xing Fang et al. — Tue, 24 Mar 2009 10:02:52 PDT

The Rio Grande is the fifth longest river in North America. Amistad Reservoir plays an important role for the development of sustainable water in the Rio Grande drainage basin. Reservoir management is a complex process involving not only the hydrological state of the reservoir, water quality in/downstream of the reservoir, and demands from downstream users, but also judgment weighing the risk of flood versus drought and the political positions of the two countries. This study simulates water quality in Amistad Reservoir using a two-dimensional reservoir model under various hydrological and water demand scenarios and projects water quality in the reservoir under different future climate scenarios due to potential global climatic warming. Different inflow and outflow scenarios and the initial reservoir storage condition can result in different water quality conditions in the reservoir which impact reservoir management plans. Drought in Rio Grande basin and increasing of water demand upstream and downstream of Amistad Reservoir can result in low reservoir storage. Simulations of water quality in Amistad Reservoir under different water availability and weather conditions can assist us in developing different alternative reservoir management plans. Unfavorable water quality conditions in the reservoir pose environmental and ecological concerns for the reservoir and communities downstream of the reservoir.

The Influence of Goodenough Spring on Amistad Reservoir, Texas

R. H. Kamps — Tue, 24 Mar 2009 09:59:22 PDT

Goodenough Spring is a sub-lacustrine spring situated 43 meters beneath the surface of the international Amistad Reservoir on the Rio Grande. Its source is the Edwards-Trinity aquifer and prior to its inundation in 1968, it was a very high volume and high quality tributary to the Rio Grande. Since 1968, Goodenough Spring has been mixing with the more saline water of the reservoir. However, the mixing is not uniform, leading to horizontal lenses of spring water within the strongly stratified water column during the summer and surface infusion of spring water in the winter. Spring and fall are transitional periods. From a moving boat, we have tracked winter spring flows using simultaneous 1 Hz measurements of temperature, turbidity, in vivo chlorophyll fluorescence, conductivity, pH and GPS readings. This sampling rate yields a 10 m resolution along the transects. Subsurface water column structure was inferred from spot profiles of these same parameters reading at 1 meter depth intervals at 15 locations. Goodenough Spring carries a significant NO3-N load and discharges it into the reservoir at a point far removed from other major nitrogen inputs. Water samples were also collected along the transects for subsequent NO3-N analysis. Our data indicate that Goodenough Spring is a significant contributor to the quality and quantity of water in Amistad Reservoir.

Adding Efficiency and Reducing Conflict in Reallocation Decisions of Federal Reservoirs Using Existing Rules: Some Insights from Economic Bargaining Theory

Michael C. Farmer — Tue, 24 Mar 2009 09:54:12 PDT

Large Water use reallocations of multipurpose Federal Projects, typically USCOE or BLM reservoirs, is an expanding challenge. One controversy centers on whether Congress intended policy-makers and Project managers to apply the guidelines of the WSA of 1958 or of Separable Costs, Remaining Benefits (SCRB) to manage very large reallocations (McMahon and Farmer, 2004). Rigid adherence to WSA when applied to cases beyond the incremental limits delineated explicitly in the law removes a potentially low cost and flexible means to resolve water use demand changes through improved, or adaptable, operational changes at existing multipurpose reservoirs. Simply, the very real management advantage of the WSA to streamline minor reallocation decisions becomes a strangle-hold on policy flexibility for large and complex reallocations when multiple uses are subject to reassessment. SCRB, traditionally relegated to evaluate new construction, is a permissible evaluation tool to use for reallocation. SCRB introduces more economically efficient reallocation decisions by linking operational priority to National Economic Development (NED) benefits. Less obvious, even counterintuitive, is the potential for SCRB to expand consensus opportunities to resolve water use demand changes by interpreting the operational application of joint costs (as stated) in light of economic principles. The focus on complementarities that SCRB underlines allows managers to meet several water use demands from the same standing infrastructure in a fashion that mirrors closely multiparty bargaining theories that can help to avert conflict, at times prevent costly new construction projects, and also to improve performance of the economy - all within existing rules and legislation.

Moving Towards More Efficient Water Markets: Institutional Barriers and Innovations

Charles W. Howe — Tue, 24 Mar 2009 09:45:26 PDT

In the western U.S., one finds a few water markets that function quite efficiently from an economic point of view. Most water markets, some operational for over a hundred years, are highly imperfect, characterized by high transaction costs, asymmetric information on buyer & seller sides, long administrative or legal processes, and excessive brokerage fees. The question is What features of the relatively efficient water markets account for their success and how many of these features can be carried over to the larger set of inefficient water markets?. What changes in the legal and institutional frameworks would be required? Examples will be presented, starting with the Northern Colorado Water Conservancy District's market for permanent transfers as a benchmark, contrasted with major examples of inefficient transfer processes undertaken by Denver suburbs in the last several years. The functions of traditional legal doctrines/practices such as no injury, beneficial use, forfeiture through non-use, and required drying-up of irrigated land upon sale of water are evaluated from an economic point of view and seriously questioned.

The Evolving State of Ground Water Right Transfers in Idaho

Gary Johnson et al. — Tue, 24 Mar 2009 09:41:02 PDT

In Southern Idaho, as in most of the western US, available fresh water supplies are essentially fully appropriated and future economic growth depends upon the ability to transfer water rights from lower value uses. These transfers often involve a change in use of the water as well as a change in location of the point of diversion. The change in location creates special administrative challenges when dealing with ground water rights. The effects of ground water use can propagate throughout an aquifer and affect nearly every ground and surface water user in the basin. A spreadsheet based Ground Water Rights Transfer Tool has been applied in the Eastern Snake River Plain in southern Idaho for several years. The Transfer Tool uses a ground water flow model of the aquifer to calculate the hydrologic effects of changes in well location on surface and ground water exchange in 11 different reaches of the Snake River. Typically, the rate or volume of a right will be decreased in the transfer process because of increased levels of impact to one or more of the 11 reaches of the Snake River.

Structuring Dry Year Land Fallowing to Improve Supply Reliability

Bonnie G. Colby — Tue, 24 Mar 2009 09:36:01 PDT

Water supply reliability is a major concern for water users in regions subject to prolonged drought. In much of the western US, agricultural districts hold the most senior and reliable water rights. Access to this water during drought is of great interest to those with less reliable water portfolios. Temporary water transfers conditioned on drought conditions have been used in a number of locations worldwide to firm less reliable supplies. This presentation summarizes the most innovative features of these programs and proposes a structure for regional dry year fallowing programs in the western U.S. Specific concerns addressed include compensation for agricultural water users, third party impacts, equity issues among agricultural interests, effects of drought on water prices and cost effectiveness in achieving more reliable supplies. The presentation is based on research conducted over the last two years in collaboration with public agencies, water users and NGOs.

The Dominant Water Estate

Olen Paul Matthews — Tue, 24 Mar 2009 09:33:26 PDT

The United States and other common law countries have a rich tradition of protecting property rights in land. In fact in earlier times these land rights included water as part of the right. Remnants of this are still visible in the riparian rights doctrine for surface water and in some ground water doctrines. Traditionally land use practices were protected even when they interfered with water usage. But in dry areas the dominance of land rights over water rights does not make sense. Water is more valuable than land in arid locations. Shouldn’t water be protected from land use practices that interfere with water uses? If water rights were dominate over land rights, would more water be conserved or would water be put to more efficient uses? Mineral rights can be severed from other land rights, and when they are the right to develop the mineral is included with the mineral right. This makes the mineral estate dominant. If water rights were dominant over land rights, land uses that impacted water would only be allowed if there was also an accompanying water right. The basis for this already exists in many western states where the state or the public is considered the original possessor of all water rights. Individual uses and rights are allowed but only under a state permit system. My paper examines the concept of the dominant water estate and explores what this would mean for increasing water supplies.

Solar Desalination

Veera Gnaneswar Gude — Tue, 24 Mar 2009 09:27:22 PDT

This study evaluated the feasibility of utilizing low-grade heat sources such as solar energy and waste heat from industrial processes for desalination. The premise of the approach is that saline waters can be desalinated by evaporation and condensation of fresh water at near-ambient temperatures at low pressures. Low pressures can be achieved naturally in the head space of water columns of height equal to the local barometric head. By connecting the head space of such a saline water column to that of a distilled water column, and by maintaining the temperature of the former about 15-20 degrees C above that of the latter, fresh water can be evaporated from the saline column and condensed in the distilled water column. In this study, it is proposed to use thermal energy storage (TES) system to heat the head space of the saline water column. The TES can be maintained at the desired temperature using solar energy and/or waste heat from thermal power plants, refrigeration plants or air conditioning units. This paper presents an integrated process model developed to evaluate the feasibility of combining solar energy with an absorption refrigeration system (ARS) to provide the energy to the TES. Results of this study show that the heat rejected by an existing ARS of cooling capacity of 3.25 kW (~1 ton of refrigeration) is adequate to produce desalinated water at a rate of 5 kg/hr, with an additional energy input of 150 kJ/kg of desalinated water. The total solar panel area required for this application was 25 m² . Performance curves and guidelines for preliminary design of such an integrated system are presented.