10/08 - Centralized Water Use Database for the Republican River Basin in Southwest Nebraska: An NET Summary

The way irrigation water use is monitored and documented is bound to change with the development of new technologies that are capable of remotely reading irrigation flow meters and archiving the records in a centralized water use database.

University of Nebraska-Lincoln (UNL) irrigation engineers Suat Irmak and Lameck Odhiambo, both of UNL’s Department of Biological Systems Engineering, are implementing a next generation pilot project on automated irrigation water use monitoring and data collection for addressing current and future water issues.

The project is being piloted in the Middle Republican Natural Resource District (MRNRD) and was funded by the Nebraska Environmental Trust (NET) for a three year period (2012-2015). Long-term goal is to establish a basin-wide automated irrigation water use monitoring and database that can enhance accurate measurements and proper documentation of water use in the Republican River Basin.

MRNRD is one of 14 NRDs charged with promoting a sustainable balance between water use and supply so that the area’s economic viability in terms of sustainable use of water resources can be achieved and maintained for both the near and long terms. MRNRD in collaboration with three other NRDs that cover the Republican River Basin on the Nebraska side (i.e. Upper Republican NRD, Tri-Basin NRD, and Lower Republican NRD) have developed a joint Integrated Management Plan (IMP) for ground water and surface water resources.

One of the key elements needed for successful IMP implementation is accurate monitoring and documenting the amount of groundwater withdrawal for irrigation. Currently, groundwater withdrawals are monitored from a network of metered irrigation wells.

There are over 24,000 active irrigation wells on the Nebraska side of the basin, with about 3,300 of those in the MRNRD. The present practice of gathering irrigation water use data is by NRD technicians to manually read irrigation meters once a year after irrigation season. That data is then manually entered and compiled in an MS Access database and stored at the NRD.

The process is laborious, expensive, time consuming, and subject to human error. In addition, taking readings only once a year after the irrigation season does not provide sufficient data on how and when water is used during the growing season in relation to crop water requirements. Consequently, water managers at the NRDs lack accurate, detailed, and timely enumeration of water quantities that can be used for planning irrigation during the irrigation season.

To effectively manage its long-term water usage in a sustainable and equitable manner, the NRDs need a more accurate and efficient method for continuous data collection. Accurate measurement and documentation of the quantities of water use can provide critical input data for improving the integrated water management and planning processes.

A centralized water use database is described as an organized collection of water use information located and maintained in one location and not spread across multiple sites. There are several advantages of a centralizing the database, including ability to access all information in one location; easier organization in a single location; faster database searches because there is no need to check multiple locations; easily upgradable to handle more information by simply adding servers to the database location; and a centralized database is easier to physically secure.

This project uses the most appropriate and cost effective, yet advanced technology for automated irrigation water measurements and data collection system. Irrigation fields are remotely connected to a centralized database. The system consists of transmitters installed at the bases of existing irrigation flow meters. The transmitters transmit pulses representing irrigation flow rates to stand alone telemetry units that convey the data to telemetry gateway (server).

Other related water use data/variables that are measured and transmitted through the telemetry system include rainfall, potential evapotranspiration and soil moisture. The system can record and deliver real time irrigation flow and other data via the Internet to a centralized monitoring computer. This time and transportation costs by eliminating the need to drive to each meter for site reading and manually recording flow data.

The project is being implemented under the aegis of the Nebraska Agricultural Water Management Network (NAWMN). Irmak established NAWMN in 2005 to transfer high quality research-based information to farmers and crop consultants to enhance their decision-making process and adoption of newer tools and technologies that will enable irrigators to conserve water and energy resources and enhance crop water productivity.

It has an established network of more than 1,200 farmers, crop consultants and 17 NRDs as partners/cooperators, along with UNL Extension educators, Natural Resources Conservation Service (NCRS), and irrigation districts. Currently, other NAWMN projects include research-based tools such as evapotranspiration gages (ET gages; atmometer), and soil moisture sensors installed in many parts of Nebraska in a coordinated form.

Strong and effective collaboration between UNL and various state and federal water management agencies to maximize net benefits of irrigation water management in crop production will continue to be very important in Nebraska, because many areas in the state are involved in significant management changes to conserve water. Education and new information about the use of appropriate technologies are delivered to agriculture professionals and irrigators through NAWMN. Irrigation water metering and real-time monitoring of irrigation water implemented through automated water use database project will make it possible for greater water saving strategies to be developed on a watershed/basin scale.

Within the MRNRD automated water use database project, 30 participating farms were selected from among all registered irrigation well permits in MRNRD. Participating farms have access to monitor their own irrigation data via the internet using their home computers.

With real time data delivery capability, water management staff at the NRDs and irrigators are able to monitor water-use quantities from their home computers, and set alarms (if desired) to indicate high/low usage rates, and track data by individual farm number.  When fully implemented, the benefits of this project will be a significant reduction in cost of data collection and processing. When accurate and timely irrigation flow measurement is correlated with crop water requirement, water usage by growers can be reduced by an estimated 20 to 40 percent. The quality of groundwater which is a source of drinking water for more than 19,000 people living in the project area will be protected through the reduction of deep percolation of irrigation water that carries nitrate nitrogen out of the root zone into the groundwater.

Surface water quality will also benefit from this project as better water management will reduce irrigation water runoff that would impact streams and lakes with sediments laden with agricultural chemicals. These benefits will be achieved with training the farmers in irrigation best management practices supported by research-based data from this project. Another benefit is to help enforce compliance with the IMP ground water pumping limits

The project has already established protocol for remote data reading, transmission and archiving to a centralized database. An NRD-wide Geographic Information System (GIS) is being developed for cataloging data and irrigation system locations within MRNRD. The GIS will be used for coordination of inputs and reporting of the data on crop and soil type on a weekly and monthly basis. In addition, agricultural and environmental information pertinent to irrigation water use will be gathered from other existing sources and will be geographically referenced.

Actual crop evapotranspiration and irrigation water requirements are calculated for the crops grown, and the crop water requirements are compared with the actual amount of irrigation water applied to assess the irrigation performance practiced by farmers. Educational programs are being conducted to make recommendations on improvements in irrigation management, mainly to bring irrigation water requirement, and actual water applied close to each other to minimize over- or under-irrigation.

(Editor’s note: From the Nebraka Environmental Trust newsletter)