Evaluation of the CRITERIA Irrigation Scheme Soil Water Balance Model in Texas – Initial Results

The CRITERIA model was created in the 1990s in Italy, and is based on the soil water balance computation procedures developed at the Wageningen University in the Netherlands in the 1980s. CRITERIA has been used as an analysis and regional water planning tool (e.g seasonal crop yield and water use predictions, impact of climate change scenarios), and is currently used in Northern Italy to update the regional water balance on a weekly base. The model can handle a multilayered soils and computes daily average values related to the soil water balance (actual evaporation and transpiration, water flow between layers, deep percolation, surface runoff, and subsurface runoff). Automatic algorithms allow for calculation and scaling of data which may not be available such as detailed meteorological data and soil-water properties. Outputs can be readily used in a Geographic Information System (GIS). The required inputs are precipitation, air temperature, soil texture, and crop management data (planting and harvesting dates, irrigation method and applied volumes). The model allows for input of additional data such as actual ET, soil conductivity, and soil-water characteristics. If this data is not available, the model can estimate them. The model requires calibration using a combination of measured soil moisture and actual ET. The purpose of the study was to: Evaluate the performances of CRITERIA in predicting soil water moisture; and, Evaluate its potential for predicting crop water requirement in real time within irrigation schemes using minimal input data We calibrated the model for two (2) sites: the Texas High Plains with conditions representative of the southern Great Plains, and the semi-tropical Lower Rio Grande Valley (LRGV). Additionally, we evaluated the model without calibration for use at the irrigation district level, by simultaneously simulating many fields with different crops and water management strategies. In the Texas High Plains, the model was calibrated and compared to lysimetric data for soybean production at the USDA-ARS Laboratory, Bushland, on soybean, over a two year period (2002 and 2003). In the LRGV, data was collected from a 27-ha sugarcane field within the Delta Lake Irrigation District, over a three years period (2007-2009). As sugar cane was not present in the CRITERIA database, we used one of the available crops (Actinidia) and we modified the default values for some parameters. Data on ETo and soil-water characteristics were not available, therefore we estimated them with the model. We also measured soil-water characteristics in laboratory from undisturbed soil cores collected in the field, and compared them to the values estimated with CRITERIA, and the Soil Water Characteristics Calculator (SWCC), an easy to use tool by USDA and Washington State University. The developed district scale evaluation was carried out at the Brownsville Irrigation District (BID) over a season’s worth of data (year 2010) for approximately 170 individual fields. Soil moisture prediction at the Bushland and Delta Lake sites was in good agreement with measured data (R2 of correlations ranged between 0.7 and 0.8). At the Bushland site, the root growth model did not describe well the actual soybean growth below 30 cm of depth, probably due to the existence of the thick clay layer at 30 cm of depth which caused an atypical shaped root zone. When applied at district scale, CRITERIA accurately predicted changes in soil moisture with estimated input data such as crop planting and harvesting dates, and actual irrigation volumes. One product of this study was a soil moisture status map that could be updated on a daily base. CRITERIA needs additional improvements for application at field level in Texas conditions, particularly the crop management component (e.g. add crops and irrigation methods, improve root growth model). In order to apply the model as real time decision support system at regional scale, additional improvements are needed, including in the scaling algorithms and the automation of data and GIS output. Finally, further evaluation should be carried out to evaluate model algorithms currently used to estimate soil water properties

Methodologies for Analyzing Impact of Urbanization on Irrigation Districts

The region of Texas along the Mexican border has been experiencing rapid urban growth. This has caused fragmentation of many irrigation districts who are struggling to address the resulting challenges. In this paper, we analyze the growth of urban area and its impact on water distribution networks in three Texas border counties over the ten year period, 1996 to 2006. In particular, we discuss alternative procedures to assess such impacts, and we evaluate their effectiveness in identifying critical areas. Identification of urbanized areas was carried out starting from aerial photographs using two different approaches: manual identification of areas “no longer in agricultural use” and automatic extraction based on the analysis of radiometric and structural image information. By overlapping urbanization maps to the water distribution network, we identified critical areas of impact. This impact was expressed as density of network fragments per unit area, or Network Fragmentation Index (NFI). A synthetic index per each district, District Fragmentation Index (DFI) was obtained by dividing the number of network fragments by the total district length of network. Results obtained starting from manual and automatic maps were comparable, indicating that the automatic urbanization analysis can be used to evaluate impact on the water distribution network. To further identify critical areas of impact, we categorized urban areas with the Morphological Segmentation method, using a software available online (GUIDOS). The obtained categories (Core, Edge, Bridge, Loop, Branch, and Islet) not only improved the description of urban fragmentation, but also permitted assigning different weights to further describe the impact on the irrigation distribution networks. The application of this procedure slightly shifted the areas of impact and grouped them in more easy-to-interpret clusters. We simplified urbanization analysis by identifying a probability of network fragmentation from network and urbanization density maps. Although results were comparable to the ones obtained with the other methods, additional validation is recommended. These methods look promising in improving the analysis of the impact of urban growth on irrigation district activity. They help to identify urbanization and areas of impact, interpret growth dynamics, and allow for partial automation of analysis. It would be interesting to collaborate with irrigation districts to determine the correlation between the real impact on the district operation and the elements of the water distribution network included in the analysis

Evaluation of Smart Irrigation Controllers: Year 2011 Results

A smart controller testing facility was established by the Irrigation Technology Center at Texas A&M University in College Station in 2008 in order to evaluate their performance from an "enduser" point of view. The "end-user" is considered to be the landscape or irrigation professional (such as a Licensed Irrigator in Texas) installing the controller. Controllers are tested using the Texas Virtual Landscape which is composed of 6 different zones with varying plant materials, soil types and depths, and precipitation rates. This report summaries the results from the 2011 evaluations. Nine controllers were evaluated over a 152 day period, from April 11 - May 29, 2011 and August 8 to November 20, 2011. Controller performance was analyzed for each seasonal period (spring, summer, fall). Controller performance is evaluated by comparison to the irrigation recommendation of the TexasET Network and Website, as well as for irrigation adequacy in order to identify controllers which apply excessive and inadequate amounts of water

Use of GIS as a Real Time Decision Support System for Irrigation Districts

The objectives were to provide the districts with a simple tool that would improve the availability of pumps and gates data from the existing SCADA system, improve the management of water orders, and allow access of data by account holders through the internet. An important component of the project was to interact and train District personnel. The final product of the project is a website, where pump and gates operations and water orders information are displayed in real-time, along with links to related historical data and other information. The on-line tool has three main components: 1) possibility to query real time and historic data from a new reorganized database created in our server; 2) status maps for display in real time of selected spatial information and alarms; 3) interactive maps for display of desired spatial information in real time and query historic spatial information. The main meaning of the status maps is to enable a friendlier and quicker access to the frequently used data. SCADA data include On/Off, current flow, upstream and downstream water level, and gate position. Water account data include pending orders, payment delinquents, and water balances

Chemigation Equipment and Safety.

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EM-105 Expansion of Urban Area in Irrigation Districts of the Rio Grande River Basin, 1996 - 2006: A Map Series

The border region of Texas is experiencing rapid urban growth which is expected to have a continuing and increasing impact on the irrigation districts of the region. This report presents an analysis of the expansion of urban area during the ten year period from 1996 to 2006 in portions of the Rio Grande Basin. This report includes maps of five counties: El Paso, Maverick, Cameron, Hidalgo and Willacy, which show the expansion of urban area over this ten year period. Also, shown on the maps are the service areas of 30 irrigation districts. Individual maps of the districts have been distributed to each district and are posted at http://idea.tamu.edu. Hudspeth and Presidio Counties (and their associated irrigation districts: Hudspeth County Conservation and Reclamation District No.1 and Presidio County Water Improvement District No.1) are not included in this map series due to insignificant urban growth