Irrigation management strategies for improved salinity and sodicity control

An integrated approach is developed to assess a priori the effects of irrigation management interventions on soil salinity, sodicity and transpiration. The approach is tested for a 75,000 ha irrigation system in Pakistan, where canal and groundwater are used conjunctively. The main hypothesis is that by reallocating good quality canal water, the use of poor quality groundwater can be restricted, thus combating salinity and sodicity and mitigating their effects on crops. The study has three components. Firstly, interventions in canal water deliveries to tertiary units are analyzed using an unsteady state hydraulic model, based on the St. Venant equations, and linked with a regulation module, which captures the operational decisions of the irrigation agency. By changing the operational rules at the main canal, and by redimensioning the outlets in secondary canals, the water can be distributed equitably to tertiary units or delivered to those units that require it for salinity control. Secondly, the impact of irrigation on salinity, sodicity and transpiration is assessed for farmers' fields, using a combined soil water flow and solute transport model, based on Richard's equation and the convection-dispersion equation, and a regression equation, based on the irrigation quality and soil texture. A curvilinear relationship with a decreasing tangent was found between the irrigation quantity and sod salinity. Increases in the EC of the irrigation water result in a parallel curve with higher salinity levels. Adapting the irrigation quantity and quality to the existing soil types and depth to groundwater table can, therefore, reduce salinity and sodicity, thus 'avoiding soil degradation, which already occurs at an ESP of 4%. Thirdly, both components are combined with a parallel, socio-economic study, where farmers' decisions related to the crop portfolio and acquisition/application of water, were captured in Linear Programming models. The individual models of both studies are interfaced to develop a tool, capable of quantifying the effect of irrigation management interventions. For a secondary canal serving 14,000 ha, it is shown that the area threatened by sodicity is reduced by 40% by reallocating canal water, without affecting the agricultural production. The results of the developed tool should not be taken as accurate predictions, as there are likely to be unforeseen events due to the complexity of irrigation systems. Instead, the approach should be evaluated for its effectiveness in supporting actors' decisions in irrigation system management, by enhancing their understanding of the effects of interventions on salinity, sodicity and agricultural production. The application of the approach, in two case studies, shows that it allows the investigation of a wide range of policy and management interventions, and captures adequately the complexity of an irrigation system, thus providing indications about its transferability. However, the tools should be applied as part of an integrated concept, which includes phases of diagnosis, identification of relevant processes and parameters, and discussions with actors

USCID water management conference

Presented at Meeting irrigation demands in a water-challenged environment: SCADA and technology: tools to improve production: a USCID water management conference held on September 28 - October 1, 2010 in Fort Collins, Colorado.Includes bibliographical references.The Colorado Satellite-Linked Water Resources Monitoring System: 25 years later -- Using state water law for efficient water use in the West -- On-farm strategies for deficit or limited irrigation to maximize operational profit potential in Colorado's South Platte Basin -- Economics of groundwater management alternatives in the Republican Basin -- Effects of policies governing water reuse on agricultural crops -- Flow calibration of the Bryan Canal radial gate at the United Irrigation District -- Considering canal pool resonance in controller design -- Synthetic canal lining evaluation project -- South Platte Ditch Company: demonstration flow monitoring and data collection project -- The case for ditch-wide water rights analysis in Colorado -- Bore wells: a boon for tail end users -- Irrigation efficiency and water users' performance in water management: a case study on the Heran distributary, Sanghar, Sindh, Pakistan -- Initiating SCADA projects in irrigation districts -- Use of GIS as a real time decision support system for irrigation districts -- Interaction of Advanced Scientific Irrigation Management (ASIM) with I-SCADA system for efficient and sustainable production of fiber on 10,360 hectares -- Improving irrigation system performance in the Middle Rio Grande through scheduled water delivery -- Cost-effective SCADA development for irrigation districts: a Nebraska case study -- Accomplishments from a decade of SCADA implementation in Idaho's Payette Valley -- Critical success factors for large scale automation experiences from 10,000 gates -- Mapping ET in southeastern Colorado using a surface aerodynamic temperature model -- Alfalfa crop coefficients developed using a weighing lysimeter in southeast Colorado -- Turfgrass ET from small lysimeters in northeast Colorado -- Monitoring turf water status with infrared thermometry -- Training tool for on-farm water management using heuristic simulation software -- Water production functions for high plains crops -- Assessment of economic and hydrologic impacts of reduced surface water supply for irrigation via remote sensing -- Developing corn regional crop coefficients using a satellite-based energy balance model (ReSET) in the South Platte River area of Colorado

Analyzing alternative policy instruments for the irrigation sector : an assessment of the potential for water market development in the Chishtian Sub-division, Pakistan

The increasing scarcity of water and financial resources has made the economic dimension of water an important element of irrigation sector policies. Water pricing is the means traditionally used to incorporate economic issues into irrigation sector policies. More recently, water markets have been proposed as an alternative to water pricing. From a theoretical point of view, water markets are expected to lead to an efficient allocation of water among water users, as well as to improve water use economic efficiency. However, the discrepancy between theoretical requirements and the existing characteristics of the irrigation sector is significant. Therefore, the potential for water markets in managing water resources is questioned.In Pakistan, consideration has recently been given to water markets as a means to improve the performance of irrigated agriculture. The present study investigates issues related to water markets in Pakistan using the example of the Chishtian Sub-division, an irrigation system located in the South-Punjab. Within the framework of an integrated approach that combines hydraulic, soil and economic issues, the study analyses the functioning and impact of existing surface and groundwater markets that have developed spontaneously within the tertiary units of the irrigation system. Although constraints remain on the functioning of these markets, water transactions significantly improve the flexibility in managing water resources without threatening significantly the sustainability of irrigated agriculture.This study also discusses elements related to the technical feasibility of water markets at higher spatial scales in the irrigation system, and their potential impact on agricultural production and the physical environment. The potential for reallocation of surface water in terms of increased farm gross income is the highest within and between tertiary units. Also, the impact of reallocation on farm gross income is higher when volumes of surface water are transacted independently of the time of the year, as opposed to yearly reallocations that would affect proportionally the supply of canal water received each month. Constraints related to the existing conveyance infrastructure are not seen as a major obstacle to water transactions. Changes in the operational rules required to develop water markets at higher spatial scales, however, may represent an important constraint to water market development. Also, the absence of storage facility limit the potential for temporal reallocation of surface water, thus the overall impact of potential water markets.The thesis concludes by emphasizing the importance of a combination of interventions to manage the irrigation sector, as well as to improve its performance in terms of agricultural production and sustainability. The need to analyze, compare and combine interventions, further stresses the relevance of an integrated approach that integrates disciplines, links decisional and bio-physical processes, and investigates the heterogeneity of these processes within the irrigation system

Ground water and surface water under stress

Presented at Ground water and surface water under stress: competition, interaction, solutions: a USCID water management conference on October 25-28, 2006 in Boise, Idaho.Includes bibliographical references.The A&B Irrigation District in south-central Idaho supplies water to irrigate over 76,000 acres. The district's 14,660-acre Unit A is supplied with water from the Snake River. Unit B is comprised of 62,140 acres of land irrigated by pumping groundwater from the Eastern Snake Plain Aquifer (ESPA) using 177 deep wells. Pumping depths range from 200 to 350 feet. Water from Unit B wells is distributed to irrigated lands via a system of short, unlined lateral canals averaging about 3/4-mile in length with capacities of 2 to 12 cfs. During the period from 1975 to 2005, the average level of the ESPA under the A&B Irrigation District dropped 25 ft and as much as 40 ft in some locations. This has forced the district to deepen some existing wells and drill several new wells. To help mitigate the declining aquifer, the district and its farmers have implemented a variety of irrigation system and management improvements. Improvements have involved a concerted effort by the district, landowners, and local and federal resource agencies. The district has installed variable speed drives on some supply wells, installed a SCADA system to remotely monitor and control well pumps, and piped portions of the open distribution laterals. This has permitted farmers to connect farm pressure pumps directly to supply well outlets. Farmers have helped by converting many of their surface irrigation application systems to sprinklers, moving farm deliveries to central locations to reduce conveyance losses, and installing systems to reclaim irrigation spills and return flows

Ground water and surface water under stress: competition, interaction, solutions

Presented at Ground water and surface water under stress: competition, interaction, solutions: a USCID water management conference on October 25-28, 2006 in Boise, Idaho.Includes bibliographical references.Overview of the Pecos River basin -- Integrating water management in Egypt: from concept to reality -- Evaluation of the Pecos River Carlsbad Settlement Agreement using the Pecos River Decision Support System -- Collaborative solutions to complex problems: a Pecos River basin, New Mexico case study -- Development of replacement water supplies by the Lower Arkansas Water Management Association -- Integrated water management in the Bear River basin -- Looking for trouble: anticipating impacts of changing allocation of irrigation water -- AgriMet: a tool for irrigation water management -- Application of MODIS and Landsat based evapotranspiration for western states water management -- Calibrating satellite-based vegetation indices to estimate evapotranspiration and crop coefficients -- Reducing Ogallala withdrawls by changing cropping and irrigation practices in the Texas High Plains -- Evaluating cotton yield potential in the Ogallala aquifer region -- A fully automated center pivot using crop canopy temperature: preliminary results -- Deficit irrigation in alfalfa as a strategy for providing water for nonagricultural uses -- An infrastructure management system for enhanced irrigation district planning -- Gila River Indian Community Water Resources Decision Support System - a modeling system for managing a multi-source conjunctive use water supply for long-term sustainability -- Groundwater analysis tool: a component of the Water Resources Decision Support System for the Gila River Indian Community -- Effective water management through farmer participation -- Improving canal water management through participatory approach: a case study on secondary canal (Potho Minor), Sindh, Pakistan -- Groundwater management improvements to mitigate declining groundwater levels - a case study -- An on-line advisory program for optimum irrigation management -- Institutional reforms in the water sector of Pakistan -- Matching irrigation supply and demand in Egypt -- Drought risk management for irrigated potato production in Idaho -- Case study - statistical forecasting techniques for evaluating an interruptible supply contract -- Managing across groundwater and surface water: an Australian 'conjunctive licence' illustration of allocation and planning issues -- Decentralized flow monitoring in Egypt -- High rate irrigation for groundwater recharge -- Impervious synthetic lining of deteriorated concrete canals - what are the real cost and benefits to irrigation districts? -- Design and installation of a flume to monitor spring discharge at the headwaters of the Verde River -- Optimal allocation of limited water supply for a large-scale irrigated area -- Assessment of the environmental sustainability of irrigated agriculture in a large-scale scheme - a case study

Ground water and surface water under stress

Presented at Ground water and surface water under stress: competition, interaction, solutions: a USCID water management conference on October 25-28, 2006 in Boise, Idaho.Includes bibliographical references.The METRIC evapotranspiration (ET) estimation model was applied using MODIS (Moderate Resolution Imaging Spectroradiometer) satellite images in New Mexico to evaluate the applicability of MODIS images to ET estimation and water resources management. With the coarse resolution of MODIS (approximately 1km thermal resolution), MODIS was not found to be suitable for field-scale applications. In project and regional scale applications, MODIS has potential to contribute to ET estimation and water resources management. MODIS based ET maps for New Mexico were compared with Landsat based results for 12 dates. Average ET calculations using MODIS and Landsat applications were similar, indicating that MODIS images can be useful as an ET estimation tool in project and regional scale applications

Water rights and related water supply issues

Presented during the USCID water management conference held on October 13-16, 2004 in Salt Lake City, Utah. The theme of the conference was "Water rights and related water supply issues."Includes bibliographical references.Proceedings sponsored by the U.S. Department of the Interior, Central Utah Project Completion Act Office and the U.S. Committee on Irrigation and Drainage.Consensus building as a primary tool to resolve water supply conflicts -- Administration to Colorado River allocations: the Law of the River and the Colorado River Water Delivery Agreement of 2003 -- Irrigation management in Afghanistan: the tradition of Mirabs -- Institutional reforms in irrigation sector of Pakistan: an approach towards integrated water resource management -- On-line and real-time water right allocation in Utah's Sevier River basin -- Improving equity of water distribution: the challenge for farmer organizations in Sindh, Pakistan -- Impacts from transboundary water rights violations in South Asia -- Impacts of water conservation and Endangered Species Act on large water project planning, Utah Lake Drainage Basin Water Delivery System, Bonneville Unit of the Central Utah Project -- Economic importance and environmental challenges of the Awash River basin to Ethiopia -- Accomplishing the impossible: overcoming obstacles of a combined irrigation project -- Estimating actual evapotranspiration without land use classification -- Improving water management in irrigated agricultue -- Beneficial uses of treated drainage water -- Comparative assessment of risk mitigation options for irrigated agricutlrue -- A multi-variable approach for the command of Canal de Provence Aix Nord Water Supply Subsystem -- Hierarchical Bayesian Analysis and Statistical Learning Theory II: water management application -- Soil moisture data collection and water supply forecasting -- Development and implementation of a farm water conservation program within the Coachella Valley Water District, California -- Concepts of ground water recharge and well augmentation in northeastern Colorado -- Water banking in Colorado: an experiment in trouble? -- Estimating conservable water in the Klamath Irrigation Project -- Socio-economic impacts of land retirement in Westlands Water District -- EPDM rubber lining system chosen to save valuable irrigation water -- A user-centered approach to develop decision support systems for estimating pumping and augmentation needs in Colorado's South Platte basin -- Utah's Tri-County Automation Project -- Using HEC-RAS to model canal systems -- Potential water and energy conservation and improved flexibility for water users in the Oasis area of the Coachella Valley Water District, California

Irrigation and drainage in the new millennium

Presented at the 2000 USCID international conference, Challenges facing irrigation and drainage in the new millennium on June 20-24 in Fort Collins, Colorado.Irrigation scheduling has been promoted as management tool to minimize irrigation water application, however, few irrigators regularly followed any rigorous scheduling methodology. Kansas State University Research and Extension in conjunction with an irrigation association, Water PACK, began a long-term project to promote ET based irrigation scheduling and other management technology. Area irrigators serve as the focal point of the project and over time have been asked to assume responsibility of scheduling the project fields. A long-term commitment and on-farm activities such as variable water application tests and center pivot uniformity tests seems to have generated confidence and acceptance of ET-based irrigation scheduling

Irrigation and drainage in the new millennium

Presented at the 2000 USCID international conference, Challenges facing irrigation and drainage in the new millennium on June 20-24 in Fort Collins, Colorado.Includes bibliographical references.In 1998, eight irrigation districts in the Lower Rio Grande Valley of Texas initiated efforts to develop GIS-based District Management Systems (DMS). This paper provides a description of GIS (geographical information system) as applied to irrigation districts, its potential for improving the day-to-day management of districts, and the progress and difficulties encountered by the 8 districts in GIS mapping and implementation. Examples of how districts are using GIS are given, along with the value and use of the DMS in a regional water planning project