63 research outputs found

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

    Get PDF
    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

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

    Get PDF
    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

    Methodologies for Analyzing Impact of Urbanization on Irrigation Districts

    Get PDF
    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

    Electric dipole polarizability of 40^{40}Ca

    Full text link
    The electric dipole strength distribution in 40^{40}Ca between 5 and 25 MeV has been determined at RCNP, Osaka, from proton inelastic scattering experiments at very forward angles. Combined with total photoabsorption data at higher excitation energy, this enables an extraction of the electric dipole polarizability αD\alpha_\mathrm{D}(40^{40}Ca) = 1.92(17) fm3^3. Together with the measured αD\alpha_{\rm D} in 48^{48}Ca, it provides a stringent test of modern theoretical approaches, including coupled cluster calculations with chiral effective field theory interactions and state-of-the art energy density functionals. The emerging picture is that for this medium-mass region dipole polarizabilities are well described theoretically, with important constraints for the neutron skin in 48^{48}Ca and related equation of state quantities.Comment: 6 pages, 3 figure

    Genetic polymorphisms of MMP1, MMP3 and MMP7 gene promoter and risk of colorectal adenoma

    Get PDF
    BACKGROUND: Matrix metalloproteinases (MMP) have been shown to play a role in colorectal cancer (CRC). More recently, MMP1, MMP3 and MMP7 functional gene promoter polymorphisms have been found to be associated with CRC occurrence and prognosis. To document the role of MMP polymorphisms in the early step of colorectal carcinogenesis, we investigated their association with colorectal adenoma risk in a case-control study comprising 295 patients with large adenomas (LA), 302 patients with small adenomas (SA) and 568 polyp-free (PF) controls. METHODS: Patients were genotyped using automated fragment analysis for MMP1 -1607 ins/del G and MMP3 -1612 ins/delA (MMP3.1) polymorphisms and allelic discrimination assay for MMP3 -709 A/G (MMP3.2) and MMP7 -181 A/G polymorphisms. Association between MMP genotypes and colorectal adenomas was first tested for each polymorphism separately and then for combined genotypes using the combination test. Adjustment on relevant variables and estimation of odds ratios were performed using unconditional logistic regression. RESULTS: No association was observed between the polymorphisms and LA when compared to PF or SA. When comparing SA to PF controls, analysis revealed a significant association between MMP3 -1612 ins/delA polymorphism and SA with an increased risk associated with the 6A/6A genotype (OR = 1.67, 95%CI: 1.20–2.34). Using the combination test, the best association was found for MMP3.1-MMP1 (p = 0.001) with an OR of 1.88 (95%CI: 1.08–3.28) for the combined genotype 2G/2G-6A/6A estimated by logistic regression. CONCLUSION: These data show a relation between MMP1 -1607 ins/del G and MMP3 -1612 ins/delA combined polymorphisms and risk of SA, suggesting their potential role in the early steps of colorectal carcinogenesis

    Efficiency of controlled drainage and subirrigation in reducing nitrogen losses from agricultural fields.

    No full text
    In northeast Italy, a regimen of controlled drainage in winter and subirrigation in summer was tested as a strategy for continuous water table management with the benefits of optimizing water use and reducing unnecessary drainage and nitrogen losses from agricultural fields. To study the feasibility and performance of water table management, an experimental facility was set up in 1996 to reproduce a hypothetical 6-hectare agricultural basin with different land drainage systems existing in the region. Four treatments were compared: open ditches with free drainage and no irrigation (O), open ditches with controlled drainage and subirrigation (O-CI), subsurface corrugated drains with free drainage and no irrigation (S), subsurface corrugated drains with controlled drainage and subirrigation (S-CI). As typically in the region free drainage ditches were spaced 30 m apart, and subsurface corrugated drains were spaced 8 m apart. Data were collected from 1997 to 2003 on water table depth, drained volume, nitrate-nitrogen concentration in the drainage water, and nitrate-nitrogen concentration in the groundwater at various depths up to 3 m. Subsurface corrugated drains with free drainage (S) gave the highest measured drainage volume of the four regimes, discharging, on average, more than 50% of annual rainfall, the second-highest concentration of nitrate-nitrogen in the drainage water, and the highest nitrate-nitrogen losses at 236 k ha-1. Open ditches with free drainage (O) showed 18% drainage return of rainfall, relatively low concentration of nitrate-nitrogen in the drainage water, the highest nitrate-nitrogen concentration in the shallow groundwater, and 51 kg ha-1 nitrate-nitrogen losses. Both treatments with controlled drainage and subirrigation (O-CI and S-CI) showed annual rainfall drainage of approximately 10%. O-CI showed the lowest nitrate-nitrogen concentration in the drainage water, and the lowest nitrogen losses (15 kg ha-1). S-CI showed the highest nitrate-nitrogen concentration in the drainage water, and 70 kg ha-1 nitrate-nitrogen losses. Reduced drained volumes resulted from the combined effects of reduced peak flow and reduced number of days with drainage. A linear relationship between daily cumulative nitrate-nitrogen losses and daily cumulative drainage volumes was found, with slopes of 0.16, 0.12, 0.07, and 0.04 kg ha-1 of nitrate-nitrogen lost per mm of drained water in S-CI, S, O, and O-CI respectively. These data suggest that controlled drainage and subirrigation can be applied at farm scale in northeast Italy, with advantages for water conservation
    corecore