Water and Energy Balance of a Riparian and Agricultural Ecosystem along the Lower Colorado River

Spatially-distributed water consumption was modeled over a segment of the Lower Colorado River, which contains irrigated agricultural and Tamarisk-dominated riparian ecosystems. For the irrigation scheme, distributed evapotranspiration data were analyzed in conjunction with point measurements of precipitation and surface flow in order to close daily and annual water balance. The annual closure error was less than 1% of the total water diversion to the area. In addition, it was found that the soil water storage component of the water balance cannot be neglected if the analysis is performed over time frames shorter than annual (e.g. growing season). Water consumption was highly uniform within agricultural fields, and all the full-cover fields were transpiring close to their potential rates. Mapping several new and existing drainage performance indicators showed that neither soil salinization nor water-logging would be of concern in this irrigation scheme. However, the quality of high-volume return flow must be studied, especially since the degraded water quality of the western US rivers is believed to act in favor of the invasive riparian species in outcompeting native species. Over the Tamarisk forest, the remotely-sensed evapotranspiration estimates were higher than the results of an independent groundwater-based method during spring and winter months. This was chiefly due to the fixed satellite overpass time, which happened at low sun elevation angles in spring and winter and resulted in a significant presence of shadows in the satellite scene and consequently a lower surface temperature estimate, which resulted in a higher evapotranspiration estimate using the SEBAL model. A modification based on the same satellite imagery was proposed and found to be successful in correcting for this error. Both water use and crop coefficients of Tamarisk estimated by the two independent methods implemented in this study were significantly lower than the current approximations that are used by the US Bureau of Reclamation in managing the Lower Colorado River. Studying the poorlyunderstood stream-aquifer-phreatophyte relationship revealed that diurnal and seasonal groundwater fluctuations were strongly coupled with the changes in river stage at close distances to the river and with the Tamarisk water extraction at further distances from the river. The direction of the groundwater flow was always from the river toward the riparian forest. Thus the improved Tamarisk ET estimates along with a better understanding of the coupling between the river and the riparian aquifer will allow the Bureau of Reclamation to re-asses their reservoir release methodology and improve efficiency and water savings

Peer Review of Teaching: ET Theory, Deficit Irrigation and Consumptive Use

A BSE Peer Review of Teaching was carried out for a graduate level course on Advanced Irrigation Management. This course has been offered for several years; each time improvements are made, but there is always a need for additional improvement. In particular, ET theory, deficit irrigation, and consumptive use are topics that the students struggle to grasp. These topics involve a relatively high level of math for an MS-level (800-level) Agricultural Systems Technology course, and the available materials on these topics either were not well developed or were not a good fit for this class. The primary objective was to develop clear lecture materials, readiness test questions, homework problems, and exam questions on these particular topics. Results from Post-Pre Survey indicated a large increase in the students’ self-assessed skills (related to learning objectives) during the semester. Future course improvements should include updating the course sequence of topics to provide a more uniform distribution of workload for the students

Irrigation water flow measurement

The Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311.Biosystems and Agricultural Engineerin

Pharmaceuticals in drinking water

The Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311.Biosystems and Agricultural Engineerin

Water measurement units and conversion factors

The Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311.Biosystems and Agricultural Engineerin

Drip irrigation systems

The Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311.Biosystems and Agricultural Engineerin

Surface irrigation systems

The Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311.Biosystems and Agricultural Engineerin

Mapping Annual Riparian Water Use Based on the Single-Satellite-Scene Approach

The accurate estimation of water use by groundwater-dependent riparian vegetation is of great importance to sustainable water resource management in arid/semi-arid regions. Remote sensing methods can be effective in this regard, as they capture the inherent spatial variability in riparian ecosystems. The single-satellite-scene (SSS) method uses a derivation of the Normalized Difference Vegetation Index (NDVI) from a single space-borne image during the peak growing season and minimal ground-based meteorological data to estimate the annual riparian water use on a distributed basis. This method was applied to a riparian ecosystem dominated by tamarisk along a section of the lower Colorado River in southern California. The results were compared against the estimates of a previously validated remotely sensed energy balance model for the year 2008 at two different spatial scales. A pixel-wide comparison showed good correlation (R2 = 0.86), with a mean residual error of less than 104 mm·year-1 (18%). This error reduced to less than 95 mm·year-1 (15%) when larger areas were used in comparisons. In addition, the accuracy improved significantly when areas with no and low vegetation cover were excluded from the analysis. The SSS method was then applied to estimate the riparian water use for a 23-year period (1988–2010). The average annual water use over this period was 748 mm·year-1 for the entire study area, with large spatial variability depending on vegetation density. Comparisons with two independent water use estimates showed significant differences. The MODIS evapotranspiration product (MOD16) was 82% smaller, and the crop-coefficient approach employed by the US Bureau of Reclamation was 96% larger, than that from the SSS method on average

Strategic planning for exchanging treated urban wastewater for agricultural water with the approach of supplying sustainable urban water: a case study of Mashhad, Iran

Considering the increasing demand for urban water and the low water-use efficiency in the agricultural sector, an exchange of treated urban wastewater for agricultural water could be a fundamental solution for administering sustainable management of water resources. However, implementing the intersectoral water exchange project is influenced by the economic, social, and environmental conditions of each region, especially in developing countries. Therefore, this study sought to identify the best possible strategies for exchanging treated urban wastewater for agricultural water in Mashhad city, located in Iran, a country that suffers from decreased urban water resources. Based on the interviews conducted with the experts and the strengths, weaknesses, opportunities and threats analysis, 28 influential factors were identified for the water exchange project, and eleven strategies were developed for its implementation. The results of the analytic hierarchy process (AHP) and F-TOPSIS indicated that organizing educational and awareness campaigns regarding the exchange project’s goals, devising an appropriate organizational structure, enhancing treated wastewater’s quality according to the WHO standards, taking the necessity of conducting social, cultural, and economic studies into account, developing consumers’ awareness programs, and supporting, training, and counseling the farmers and setting the required incentives for them were among the main factors involved in the implementation of the water exchange project in Mashhad

Agricultural irrigation with reclaimed water: Oklahoma regulation

The Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-631