Ag Water Conservation Policy

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Open Access
15th annual Central Plains irrigation conference and exposition proceedings
(Colorado State University. Libraries, 2003-02) Central Plains Irrigation Conference, author
Open Access
A binational approach to the water management in the Lower Colorado River Basin
(Colorado State University. Libraries, 1996-12) Bernal-Rodriguez, Francisco, author; Zala-Flores, Nicolás, author; U.S. Committee on Irrigation and Drainage, publisher
The Mexico-United States border is a zone of shared problems for both countries. The Colorado River system stands out among their common rivers, its usefulness benefiting many people, especially if one considers its location in a desert land, the intense competition for the river water has expounded the necessity to come to agreements between both countries, started since 1944. The Colorado river system is the most important in the United States southwest; supplies water for more than 20 million users and for large extensions of agricultural land. Besides, it is a fundamental water source for Northern Mexico, especially for the irrigation of agriculture lands in the Mexicali Valley. Water is a resource of a very high economical value in the region, because of the growing and large human population of the region, the importance of agricultural crops, and in particular, to the fact that the southern part of the basin is a desert. Inasmuch as there is an intense competition for the river water, although highly controlled, the system's management is of great interest for United States as well as for Mexico, for that reason, it corresponds to both of them. All these factors make the Colorado River management an important subject that influences the neighborhood relationship between Mexico and United States. In 1944, both countries signed a treaty on the water allotment of the three river systems shared: the Colorado, Tijuana and Bravo. According to this document, Mexico obtained the right to receive an annual delivery of 1.5 million acre-feet of Colorado River water. The construction of several dams in the Colorado River basin in the United States has had great impact on the quantity and quality of the water going to Mexico. During the last three decades, the matters related to the salinity of this water have demanded a permanent attention.
Open Access
A comparison of laboratory and field calibration of the ECH2O EC-20 soil moisture probe for soils in the Middle Rio Grande Valley
(Colorado State University. Libraries, 2012-04) Kinzli, Kristoph-Dietrich, author; Manana, Nkosinathi, author; Oad, Ramchand, author; U.S. Committee on Irrigation and Drainage, publisher
Throughout the American West irrigated agriculture has been targeted to increase water use efficiency. Soil moisture sensors offer a method to achieve efficiency improvements but have found limited use due primarily to high cost and lack of soil specific calibration equations. In this paper we examine the ECH2O EC-20 soil moisture sensor, a low cost capacitance sensor and develop a unique laboratory calibration method. Field and laboratory calibration equations were developed for 6 soil types in the Middle Rio Grande Valley. The average absolute error in volumetric water content for field calibration was 0.43 m3/m3, and 0.012 m3/m3 for the laboratory calibration. The factory calibration equation for the EC-20 was also evaluated and found to yield an average absolute error of 0.049 m³/m³. We found that the EC-20 is a reliable, cost effective, and accurate sensor, and recommend that the laboratory calibration method presented here be used to obtain maximum accuracy. We also recommend that the field calibration of the EC-20 soil moisture sensor be foregone, as this type of calibration exhibits large error rates. Additionally, it was found that the field calibration method was time consuming, covered a small range of moisture content values and was destructive to the area around installed sensors, which could lead to measurement errors.
Open Access
A GIS-based irrigation evaluation strategy for a rice production region
(Colorado State University. Libraries, 2005) Sha, Zongyao, author; Bian, Fuling, author; U.S. Committee on Irrigation and Drainage, publisher
Water shortage has become an international problem and this is especially true in China. This paper will detail the process of constructing a GIS-based information system to complete large-scale evaluation for water irrigation efficiency in a rice production region in China. A GIS-based system is built to integrate evaluation models and manage irrigation region actively and present the evaluation result in this paper. The research region is divided into several sub-regions and each sub-region is irrigated differently. After comparison of the results of different irritation methods, the suitable way of irrigation for a certain region can be selected. In this study, each rice production farm field located in sub-regions will be regarded as a basic unit and is digitalized to form spatial database. We monitor all growing stage of paddy rice and record water irrigation and rice yield. The goal is to find region-fit irrigation strategy and thus to enhance the profitability of irrigation water.
Open Access
A multi-variable approach for the command of Canal de Provence Aix nord water supply subsystem
(Colorado State University. Libraries, 2004-10) Viala, Yann, author; Malaterre, Pierre-Olivier, author; Deltour, Jean-Luc, author; Sanfilippo, Franck, author; Sau, Jacques, author; U.S. Committee on Irrigation and Drainage, publisher
The Canal de Provence is fully user oriented. Water users can take the water freely without respecting neither rotation nor any sort of priority allocation. Its structure. consisting of main free flow canals and pressurized distribution networks. is well adapted to this strategy. The main canal must be able to face the regime variations coming from this kind of distribution. The current regulation conception first split the whole system into a series of assumed independent sub-systems. The multi-variable aspect is then taken into account by a coordination of the sub-systems adjustment, carrying the discharge correction from downstream to upstream. The Aix nord branch control presents interesting characteristics such as many different hydraulic entities (free surface canals. reservoirs. pumping stations) and operating constraints (levels in reservoirs. optimization of pumping costs). A real multi-variable approach will allow managing all gate and pump operations and all constraints at the same time. leading to a global optimisation of the whole system. The MIMO (Multi Input - Multi Output) model is established from transfer functions. the coefficients of which are deduced from the physical and geometrical characteristics of the system. A Linear Quadratic Regulator is computed and tested on a complete non-linear numerical model of the hydraulic system. The system to be controlled includes many discrete commands (pump operations) that are not managed by a classical optimal control. These commands are treated apart, leading to calculated perturbations that are introduced in the regulator.
Open Access
A new direction for allocating water of the Nile River in Egypt
(Colorado State University. Libraries, 1998-10) Priest, John E., author; U.S. Committee on Irrigation and Drainage, publisher
The Egyptian philosophy of water use is that of an agrarian society even though perhaps only 50% of foodstuffs are produced domestically. The Egyptian Government is now implementing a plan of action that will spread water over vast new areas of the Western Desert and the Sinai. The objective is to transfer within 20 years as many as 7 million persons from the Nile Valley and the Delta to intensively irrigated areas of the Western Desert. This diversion of Nile River water is to be accomplished even as the nine upstream riparians are demanding more water. A paradigm shift is required. Those guiding irrigation development in the Western Desert must accept and embrace a model of mixed development based on: 1) the eventual minimization of irrigation of field crops, 2) the identification and filling of now dry water-table aquifers through diversion of excess river flows in wet years, and 3) exploitation of minerals and other important resources of the Western Desert to support the new communities. Clearly, during the initial stages of New Valley developments, the government needs to divert the entire excesses of wet year flows for over-irrigation of reclamation crops and the filling of pre-identified underground reservoirs. Integrated ground-water-surface-water systems should be established., successively along the path of development, to supply municipal and industrial water and for the irrigation of vegetables and fruit trees. A large component of the water required for creating shaded communities and wind breaks should be derived from reuse of treated wastewater effluents and the pumping of mildly brackish ground water. Thus, through the establishment of water-table aquifers along the route of development and the careful husbanding of the water resource, extensive settlements can be realized in the western Desert without substantial diminishment of the productive capacity of the agriculture of the Nile Valley and Delta. Sustainability of the colonization will depend equally on the exercise of care in protecting the fragile desert environment in every zone of development and the equitable collection of water user fees from the start of project operations.
Open Access
A probabilistic assessment of reservoir fill under a range of winter flow regimes
(Colorado State University. Libraries, 1996-12) Benjamin, Lyn, author; U.S. Committee on Irrigation and Drainage, publisher
Regulated flow regimes below irrigation reservoirs frequently create undesirable conditions for downstream biota. In order to meet reservoir fill deadlines, winter discharge below Island Park reservoir on the Henry's Fork of the Snake River, eastern Idaho, has been dramatically reduced from pre-dam flows of approximately 400 cfs, affecting trout and trumpeter swan populations. The purpose of this study was to model the probability of meeting storage deadlines while providing minimum instream flows during the winter months. Five different winter release scenarios were simulated using actual outflow and reservoir storage data for each water year from 1940 to 1995, and the probability of reservoir fill was calculated for each of these scenarios. The sensitivities of reservoir fill to reservoir starting levels and fill deadlines were also compared by running the simulations with different reservoir starting levels and fill deadlines. Results indicate that the probabilities of meeting the April 1st fill deadline with winter flows of 200 and 300 cfs are 55% and 42%, respectively. Bureau of Reclamation operating procedures that link all reservoirs within the Minidoka system mandate filling Island Park by April 1st, despite the observations that irrigation water is rarely needed from Island Park before July 1st and spring runoff occurs in April and May. When later fill dates were modeled, probabilities of reservoir fill became greater. Reservoir fill is very sensitive to reservoir levels at the start of storage season; fill occurs 100% of the time by May 1st with winter outflows of 200 cfs when starting contents exceed 65,000 acre feet. These results suggest that in order to provide for both instream flow and irrigation needs, water managers consider the moving the mandated fill date for Island Park Reservoir later in the spring and implementing water conservation measures that will maximize reservoir contents at the end of irrigation season.
Open Access
A qualitative approach to study water markets in Pakistan
(Colorado State University. Libraries, 2005) Abro, Altaf A., author; U.S. Committee on Irrigation and Drainage, publisher
The government of Pakistan has recently introduced reforms to reduce the financial deficit of the country's irrigation sector. Reforms are expected to grant autonomy to irrigation agencies and transfer part of the management responsibilities to water users. Water markets are already functioning in the country, but are limited to tube-well or sub-surface water in two provinces only. Although the development of water markets is described as being efficient, little is known regarding the potential feasibility for and impact of such markets on small landholders. The government's public investment in large irrigation projects has already widened the gap between large and small landholders in terms of revenues and financial assets. It is feared that reforms will further allow for arrival of powerful landholders and businessmen from other regions that will steadily displace the small local agricultural producers. Several studies have been conducted from a quantitative perspective, but no qualitative study has been conducted that may provide insight into the equity issues in regard to water markets. Therefore, a qualitative study is proposed to investigate the affects of water markets on small landholders in Pakistan and the markets' role in the distribution of the benefits of water resources among landholders across all categories.
Open Access
A study of additional drainwater reuse for the Sutter Basin
(Colorado State University. Libraries, 2009-06) Isbell, Brett M., author; U.S. Committee on Irrigation and Drainage, publisher
Farmers in the Sutter Basin, in the Sacramento Valley of California, do not have sufficient irrigation supply to meet crop needs during peak irrigation demand and during years with surface water allocation restrictions. To help meet these needs, Reclamation District 1500 examined the viability of expanding its existing drainwater reuse system. Drought and reduced surface water allocations, which are partly attributed to ever-more-stringent environmental concerns and regulations, have markedly increased the hard-to-quantify socioeconomic value of a reliable water supply. Basin farmers have a sense of urgency to establish a supplemental irrigation supply. Expanding the drainwater reuse system for a supplemental irrigation supply will increase water delivery reliability in the Sutter Basin. Approximately 68,000 irrigated acres and over 500 miles of surface drainage channels encompass the study area, where rice is the predominate crop. This study highlights the need to identify supplemental irrigation sources in the absence of extensive master planning data. This study relied on stakeholder input to identify operational and management constraints and to develop specific evaluation criteria. Drainwater availability was inversely proportional to downstream irrigation demand in the Sutter Basin, which required special engineering consideration. The study found that drainwater quality concerns can be mitigated by (a) reusing drainwater upstream of the connate water zone, (b) blending drainwater with surface diversion water, and (c) implementing water quality monitoring program tailored to the recommended alternative. Two service-area-scale drainwater reuse alternatives are recommended to collectively provide up to 20,000 acre-feet of supplemental irrigation supply annually. Project implementation would help offset surface diversion shortages and increase water delivery reliability in the Sutter Basin.
Open Access
A subdivision policy for an urbanizing irrigation district
(Colorado State University. Libraries, 2008-05) Knell, Steven R., author; U.S. Committee on Irrigation and Drainage, publisher
An ever increasing challenge for rural irrigation districts in the agriculturally rich San Joaquin Valley of California is adjusting to urbanization while maintaining an effective and efficient irrigation water delivery system. The Oakdale Irrigation District (OID) is currently facing this challenge and has developed a Subdivision/Parcel Map Development Policy that attempts to bring balance to that concern. This paper will present OID's Subdivision Policy and discuss the reasoning behind the conditions and requirements within the policy. It is the intent of this paper to provide other irrigation districts, facing similar urbanization pressures, a foundation for development of similar policies in the hopes of preserving and protecting the water delivery systems so vital to our agricultural communities.
Open Access
A user-centered approach to developing decision support systems for estimating pumping and augmentation needs in Colorado's South Platte Basin
(Colorado State University. Libraries, 2004-10) Garcia, Luis A., author; U.S. Committee on Irrigation and Drainage, publisher
Throughout the United States, new models for computing augmentation requirements are being developed and applied. For the past eight years, I, along with my research team, the Integrated Decision Support Group (IDS), have had the opportunity to study the data and modeling needs of water users in the Lower South Platte River region in Colorado. With the active participation of the water users, IDS has prioritized the needs and then collected or generated the data and modeling tools necessary to meet these needs. This approach to Decision Support System (DSS) development is based on the premise that the user has a good understanding of what their current and future needs are, and with this in mind, we have developed an interactive and dynamic development process in which the users play an integral part. I refer to this approach as a "user-centered approach". With this approach, we have developed several data driven tools that are widely used in the South Platte Basin and other parts of Colorado. These tools are collectively called the "South Platte Mapping and Analysis Program" (SPMAP) (www.ids.colostate.edu/projects/splatte). The project has been funded by water users, the Colorado Water Resources Research Institute, Colorado Cooperative Extension, Colorado Agricultural Experiment Station, the Division 1 Office of the Colorado State Engineer, and the United States Bureau of Reclamation.
Open Access
Accomplishing the impossible: overcoming obstacles of a combined irrigation project
(Colorado State University. Libraries, 2004-10) Ploeger, Lauren C., author; Andrew, Brian J., author; U.S. Committee on Irrigation and Drainage, publisher
During the past five years of record-breaking drought, the impossible was done when the unlikeliest group collaborated in western Uintah County, Utah. Individuals from the Uintah Water Conservancy District, the Ouray Park Irrigation Company, the Uintah River Irrigation Company, and the Ute and Ouray Indian Tribes, represented by the Bureau of Indian Affairs, agreed to implement an irrigation project that would combine seven irrigation canals into a single pressurized delivery system. These individual groups had many obstacles and historical mistrust to overcome before construction even could begin on the West Side Combined Canal Salinity Project (WSCCSP). The first obstacle was to acquire sufficient funding to design and construct the five divisions of the WSCCSP. Another obstacle faced was coordinating and improving the ecological and environmental issues by increasing instream flows and tightening salinity control in order to be eligible to receive the needed Federal funding for the project. There was also the sensitive subject, especially in times of drought, of juggling the water rights of the project participants. The project areas' water rights include Native American water rights and non-Tribal water rights. Some participants have storage rights while others have only direct flow rights. Probably the most difficult obstacle was socio-economic. The historical mistrust between the entities needed to be resolved and the project participants have cooperated to share resources rather than compete for a less than adequate water supply. These obstacles, having been overcome, have resulted in very apparent project benefits. With three of the five project divisions complete, water has been conserved, water deliveries have been maximized, crops yields have increased, and the usable water supply has been increased through better efficiency and management.
Open Access
Accomplishments from a decade of SCADA implementation in Idaho's Payette Valley
(Colorado State University. Libraries, 2010) Sauer, Brian W., author; Shurtleff, Ronald, author; U.S. Committee on Irrigation and Drainage, publisher
Irrigated agriculture began in southwest Idaho's Lower Payette Valley in the 1880's. By 1900, over 30,000 irrigated acres had been developed, served by a system of over 20 canals diverting natural flows. High springtime river flows were often reduced to a trickle by August. Two Bureau of Reclamation dams were built to provide supplemental storage and to bring another 53,000 acres into production. Like many early canal systems, the Payette Valley canals were built with only a few manually operated water control structures or water measurement devices. Diversions were difficult to control due to variable river flows and much water was wasted. Water rights were difficult to administer, due to the lack of accurate water measurement. In dry years there were often disputes among users on different canals as natural flows declined. In 1997, the first canal headworks in the Payette were automated, utilizing solar power and simple off-the-shelf components. The success of this single project encouraged more irrigation entities to improve water control capabilities utilizing SCADA. New control structures were built and automated and communication links were put in place to monitor canal operations and to update water accounting. Today, there are over 40 automated control gates, 14 telemetered water measurement sites, and 11 new water measurement structures. Diversion data daily and accurately account for water use in the basin. Telemetry has enabled canal operators to monitor facilities and to respond quickly to changing water needs or emergency situations. Canal systems in the valley are being operated more efficiently, reducing both diversion rates and operational spills. This more efficient operation has helped to improve water supply reliability. These changes have also served to bring a greater sense of cooperation to water users throughout the Payette Valley.
Open Access
Administration of Colorado River allocations: the law of the river & the Colorado River water delivery agreement of 2003
(Colorado State University. Libraries, 2004-10) Harkins, Jayne, author; Snow, Robert F., author; U.S. Committee on Irrigation and Drainage, publisher
Under federal law developed over the past century, each of the seven Colorado River Basin States of Arizona, California, Colorado, Nevada, New Mexico, Utah and Wyoming has an allocation to water from the Colorado River. In addition, pursuant to a 1944 Treaty with the Republic of Mexico, the United States agreed to annual deliveries of water to Mexico. This body of law is commonly referred to as "the Law of the River." Under this legal system, the Secretary of the Interior, through the U.S. Bureau of Reclamation, is responsible for the operation of massive storage facilities in the Colorado River Basin. Primary storage in the Colorado River's Lower Basin is provided by Hoover Dam. Within the Lower Basin, California has a "basic" annual allocation of 4,400,000 acre-feet (at), yet has been using significant amounts in excess of this amount since the early 1950s, with recent use exceeding 5,300,000 af. While this use has been legal during this period, continued overuse of the Colorado River by California reduced storage amounts in system reservoirs and threatened the allocations of the other six basin states. This paper will present a case study and an overview of the history, issues, and operation of the Colorado River in the Southwest United States. This paper will have a particular emphasis on the increase in use of water in the Lower Basin and recent developments in the Lower Basin States of California, Arizona and Nevada. This paper will identify legal and operational issues that have been the subject of active negotiations by the Department of the Interior for nearly a decade. This effort, undertaken in close consultation with the seven Colorado River Basin States, lead to a successful agreement in October 2003 on a long-term transfer of Colorado River water from high priority agricultural users in the Imperial Valley to municipal users on the coastal plain in San Diego. The recently executed Colorado River Water Delivery Agreement provides a turning point in Colorado River management and operations: it provides the necessary agreement among Colorado River water users in California for an agreed-upon reduction in California's Colorado River use over the upcoming decades. With the successful implementation of this Agreement each state's allocation from the Colorado should be more secure, and these arrangements will demonstrate that there is sufficient flexibility within the Law of the River to meet the changing needs and increased demands for urban use of water in the Colorado River Basin.
Open Access
Advancing agricultural water conservation in Colorado
(Colorado State University. Libraries, 2012-04) Waskom, Reagan, author; Bauder, Troy, author; Sternlieb, Faith, author; Kallenberger, Julie, author; U.S. Committee on Irrigation and Drainage, publisher
Population growth and climate variability are increasing pressures on limited water resources, and extensive collaboration is needed to develop long-term working solutions to this complex issue. Agriculture consumes an estimated 90 percent of available water resources in the western U.S., and future water needs for an expanding urban population will likely come from agriculture. Therefore, it is increasingly urgent for farmers, water managers, extension agents, and policy-makers to understand agricultural water conservation methodology, technology, and policy to make informed management decisions. Reliable information on the subject is often not readily available to water users, especially outside of the academic and government communities. The USDA-NIFA Northern Plains and Mountains Regional Water Team (NPM) has addressed the need for increased knowledge, understanding and adoption of agricultural water conservation through an innovative web-based project. The Agricultural Water Conservation Clearinghouse (AWCC) seeks to join communities of practice to collaboratively address the complex issues of agricultural water use. The AWCC is designed as a comprehensive resource for the latest news, research, literature and tools related to agricultural water conservation. The focal point of the AWCC is a library that contains references to published materials populated by Extension specialists, research scientists, and educators, providing a refined bibliographic review of agriculture water conservation grey literature. The Library encompass over 3,600 entries of refereed journal articles, books, reports, theses and dissertations, and conference proceedings. The AWCC has been searched by over 21,000 users since it was unveiled in 2008 and participation continues to grow.
Open Access
Agricultural to urban water transfers in Colorado: an assessment of the issues and options
(Colorado State University. Libraries, 1993-12) Rice, Teresa A., author; MacDonnell, Lawrence J., author; Colorado Water Resources Research Institute, publisher
With constrains on the additional development of water supplies and in the face of growing urban demands for water cites have increasingly been turning to the water transfer process as a means of expanding their supplies. Urban encroachment onto formerly irrigated croplands long has caused the use of irrigation water to change to urban use. To make the transfers economically warranted the size of the transfers tends to be large. This transfer of large quantities of water from often rural areas with little alternative economic opportunity is prompting many western states to revisit their water transfer laws. This report examines approaches taken in the western states to both better facilitate the water transfer process and better address so-called third party effects. The report focuses initially on water transfer law and procedure in Colorado and notes that Colorado emphasizes a single kind of transaction--one in which there is a permanent purchase of a water right and a consequent total cessation of the associated activity. The report then provides a detailed evaluation of a variety of approaches used in other western states involving (1) conditioning water transfers, (2) requiring reduced water use, (3) providing incentives to conserve, and (4) facilitating short-term transfers. Finally recommendations are made for changes in Colorado law and procedure providing incentives to save water, establishing water banks, and addressing third party effects.
Open Access
Agricultural/urban/environmental water sharing: innovative strategies for the Colorado River Basin and the West
(Colorado State University. Libraries, 2011) Smith, MaryLou, author; Pritchett, James G., author; Colorado Water Institute, Colorado State University, publisher
Open Access
Agriculture and wildlife in California's Central Valley: mutually exclusive or win-win?
(Colorado State University. Libraries, 1996-06) Bias, Michael A., author; Payne, Jack M., author; U.S. Committee on Irrigation and Drainage, publisher
Because of the importance of California's Central Valley and private lands to waterfowl, Ducks Unlimited (DU) increased its conservation effort on private lands in 1990. This private land effort, delivered from DU's Western Regional Office in Sacramento, is known as Valley CARE (Conservation of Agriculture, Resources, and the Environment). Valley CARE emphasizes agricultural enhancement and wetland restoration and enhancement conservation efforts among the three geographically distinct areas of the Central Valley: the Sacramento Valley, the Sacramento-San Joaquin Delta (Delta), and the San Joaquin Valley. From surveys conducted by DU of water districts in the Sacramento Valley, during 1993-94, rice growers winter-flooded at least 90,000 acres (36,423 ha) of harvested rice fields; during 1994-95, winter-flooded rice acreages increased to over 140,000 (56,658 ha); and during 1995-96, at least 100,000 acres (40,470 ha) of harvested rice fields were winter-flooded. DU also works with farmers in the Delta to winter-flood harvested com and wheat for shorebirds, swans, geese, ducks, and other waterbirds. Cooperating landowners contributed nearly 17,000 flooded acres (6,880 ha) during 1994-95 and about 16,000 acres (6,475 ha) during 1995-% to over 30,000 acres (12,141 ha) that were flooded in the Delta during those years. The expected agronomic values and economic benefits of agricultural enhancement appear to be as high as expected and the biological values are substantial. Close to 30% of all waterbirds using rice fields are non-waterfowl species and half of these are shorebirds. DU also has expanded the Valley CARE effort in the Central Valley to establish a series of permanent wetland restorations and enhancements along with the agricultural systems. This mosaic landscape approach is fundamental to the ongoing management efforts for migratory waterbirds in California's Central Valley. This program's results demonstrate what can be accomplished when private conservation groups and agricultural organizations work together and with traditional government wildlife agencies for the mutual benefit of agriculture and conservation.
Open Access
Alfalfa crop coefficients developed using a weighing lysimeter in southeast Colorado
(Colorado State University. Libraries, 2010) AlWahaibi, Hamdan, author; Andales, Allan, author; Straw, Dalw, author; Simmons, Lane, author; Bartolo, Michael, author; Ley, Thomas, author; Trout, Thomas, author; Chávez, José, author; U.S. Committee on Irrigation and Drainage, publisher
Weighing lysimeters are precise devices used to measure crop evapotranspiration (ET) and to develop crop coefficients. A weighing lysimeter was installed in the Arkansas River Valley of Colorado in 2006 to measure ET and develop crop coefficients of locally-grown crops. The lysimeter was filled with a 3 m × 3 m undisturbed soil monolith. Alfalfa (Medicago sativa L.) was planted in the lysimeter and in 4 ha of surrounding field in August 2007. Climatic data and soil conditions were measured using microclimate and soil sensors installed above and on the lysimeter. Furrow irrigation was applied to the monolith and surrounding field. Reference ET was calculated using the hourly ASCE standardized reference ET equation. Crop coefficients of alfalfa were calculated by dividing daily measured ET from the lysimeter by the corresponding daily total ASCE standardized reference ET. Four alfalfa cuttings occurred in both the 2008 and 2009 growing seasons. The results showed that the alfalfa growth, climate and precipitation were shaping crop coefficients. The first cutting cycle, which had slower growth due to climate, had lower crop coefficients, whereas later cutting cycles with rapid growth had higher crop coefficients. The maximum crop coefficients were below 1.2 in 2008 and at or above 1.2 in 2009. Precipitation interception by the alfalfa canopy increased evaporation and caused outliers in the crop coefficient values.
Open Access
Alternatives for implementing efficiency conservation in the Imperial Irrigation District
(Colorado State University. Libraries, 2008-05) Hatchett, Stephen, author; Bliesner, Ronald, author; Eckhardt, John R., author; Davids, Grant, author; U.S. Committee on Irrigation and Drainage, publisher
In 2003 the Imperial Irrigation District (IID), a 450,000-acre water district in Southern California, entered into a package of decisions and agreements known collectively as the Quantification Settlement Agreement and Related Agreements (QSA). As part of these agreements, IID agreed to a long-term transfer of water to the San Diego County Water Authority (SDCWA) and the Coachella Valley Water District (CVWD). According to the terms of the agreements, the water must come from conservation within IID. The transfer begins small but by 2026, IID must conserve and transfer 303,000 acre-feet of water each year or nearly 10% of its total annual water use. In 2007, IID completed the Efficiency Conservation Definite Plan that outlined strategies for both delivery system and on-farm water savings. IID examined a large number of alternatives to generate the savings. Alternatives differed largely according to two features: the mix of on-farm versus delivery system savings, and the structure of the on-farm incentive program. Seven different mixes of on-farm and delivery system savings were evaluated, ranging from the maximum practical delivery system savings to generating nearly all savings on-farm. Four different incentive program approaches appeared to be viable ways of inducing sufficient on-farm enrollment. The incentive approaches differed in the way that growers would be paid for their participation. The resulting alternatives varied significantly in their performance and cost-effectiveness. Costs included system conservation measures, payments to growers to implement on-farm measures, measurement and monitoring, and administration. System delivery savings of between 93,000 and 123,000 acre-feet per year provided the most cost-effective mix of savings. The complementary on-farm savings were 180,000 to 210,000 acre-feet per year, with average payments to growers between $245 and $300 per acre-foot saved. This paper, one of seven detailing the findings of the Definite Plan, describes the development and analysis of alternatives to implement the conservation program, and summarizes important findings on how best to design on-farm conservation incentives to achieve cost-effective, real water savings without encouraging fallowing.