Influence of water temperature on the efficacy of diquat and endothall versus curlyleaf pondweed

determine the impact of water temperature on the efficacy of the contact herbicides diquat (6,7-dihydrodipyrido [1,2- α:2’,1’-c] pyrazinediium ion) and endothall (7-oxabicyclo [2.2.1] heptane-2,3-dicarboxylic acid) for control of the exotic nuisance species curlyleaf pondweed (Potamogeton crispus L.) across a range of water temperatures

Submergence in a Two-Foot Parshall Flume

The primary objective in this study was to ascertain the validity of the method of analyzing submergence developed by Hyatt (1965) in a standard 2-foot Parshall flume. The method of analyzing submergence was first developed for a trapezoidal flume (Hyatt, 1965), was later verified for a rectangular flume (Skogerboe, walker and Robinson, 1965), and has been shown by the authors to be valid for small Parshall flumes (Skogerboe, Hyatt, Johnson, and England, 1965). In view of previous findings, it was felt the method would also be valid for large Parshall flumes, and for this purpose the 2-foot flume was selected. One other objective of the study was to analyze the possibility that another, or possibly better, point of downstream measurement might be found. To accomplish this, two other points, designated c and d, were selected downstream. The downstream depth measurement is usually taken in the throat as a referenced point designated b. The resulting equations and calibration curve are listed in this report

Measuring Water with Parshall Flumes

Preface: As the value of water increases, the extent to which measurement is employed in an irrigation system also increases. Additional flow measurements provide information for improved management of the water supply. Good water management requires accurate measurement. Many devices have been developed for this purpose and are in use. Included among them are weirs, orifices, calibrated gates, Parshall flumes, and current meters. Of these, the Parshall flume is one of the most widely accepted and used. Presented in this publication is a discussion concerning the use of Parshall flumes for measuring water, including the utilization of a new approach for treating submerged flow that was developed at Utah State University. The information presented on free flow has been taken from the origianl publications of Ralph L. Parshall, and the bulletin, Measurement of Irrigation Water, prepared by Eldon M. Stock. Utilizing data developed by Ralph L. Parshall, A. R. Robinson, and the authors

Submerged Parshall Flumes of Small Size

The calibration of small Parshall flumes for measuring flows ranging in magnitude from 0.1 to 1.1 cubic feet per second (cfs) was accomplished by A. R. Robinson (1960) at Colorado State University. The purpose of Robinson’s investigation was to accurately calibrate and standardize the design of small Parshall measuring flumes. The rated flumes were constructed of galvanized sheet metal. Data was collected for Parshall flumes having throat widths of 1-, 2-, and 3- inches. Calibration tables or curves were prepared for both free and submerged flow. The dimensions of the Parshall flumes rated by Robinson are shown in Figure 1. The study reported herein was made to illustrate that the analysis of submergence developed at Utah State University (Hyatt, 1965) for trapezoidal flumes is applicable to small Parshall flumes. The data reported by Robinson (1960) is analyzed by the submergence parameters reported by Hyatt (1965) and the resulting equations and calibration curves are listed in this report

Prospects for farmer-managed irrigated agriculture in the Sindh Province of Pakistan. Final report

Farmer managed irrigation systems / Irrigation management / Water resource management / Social organization / Irrigation canals / Distributary canals / Water distribution / Equity / Water users' associations / Legal aspects / Legislation / Organizational development / Farm income / Analysis / Infrastructure / Expenditure / Costs / Drainage / Pakistan / Sindh Province

Towards environmentally sustainable agriculture in the Indus Basin Irrigation System. Final report

Irrigation systemsSurface irrigationIrrigation programsIrrigation managementEnvironmental sustainabilityRiver basinsInstitutional changeWater users' associationsDecentralizationDistributary canalsCanal regulation techniquesWater distributionWater allocationEquityInformation systemsIrrigation schedulingWatercoursesMaintenanceSocial organizationFlow measurementIrrigation practicesBasin irrigationCrop productionFurrow irrigationCottonCrop yieldWaterloggingSalinity controlConjunctive useSurface waterGroundwaterFarmers' attitudesDecision support tools