Progress 09/15/07 to 09/14/08
Outputs
OUTPUTS: Interactions between surface water and ground water can provide aquifer recharge, shallow ground water return flow, added river flow, and benefits to terrestrial and aquatic species habitat. Extensive field measurement and modeling activities took place to address the main objective of the study: to characterize the surface water and ground water interactions occurring in an irrigated valley along the Rio Grande in northern New Mexico. Irrigated field perocolation, a major component of surface water and groundwater interaction, was studied in detail on plots and fields representative of orchards and crops typical of northern New Mexico. Irrigation amount, soil water movement, and groundwater response were measured with manual and automated measurement technologies to characterize water budgets in these irrigated fields. Pairs of 12 x 12 m plots in soils representative of 85 % of the 20 km-long study area were instrumented to characterize water movement through the unsaturated zone and the shallow groundwater response following flood irrigation. Creation of a large-scale groundwater-surface water interaction model was advanced with field and modeling efforts. In order to characterize the agricultural practices and water consumption in the modeled portion of the valley, a crop survey was conducted to identify crop types, crop acreage and irrigation water consumption and a general landuse classification in the modeled area. The landuse classification map of the area was prepared by using the GIS techniques and ground truthing to identify crop types and other landuse classes such as residential, water bodies, and evergreen forests. As part of the finite-difference model to simulate the shallow groundwater-surface water interaction, a streamflow routing network was constructed including the river reach and the major acequias with field measurement of flow in 9 major acequias. A 3-phase groundwater model was constructed to simulate the steady-state flow, initial transient flow conditions and long-term transient flow conditions in the area and including the Streamflow Routing Package. Riparian vegetation accounts for an important water loss to the atmosphere in many semi-arid region valley water budgets. Effort was dedicated specifically to characterize the riparian vegetation and show how the irrigation system, in turn, supported the muliple beneficial components of the riparian vegetation. This component of the project included field surveys of near river and upland plots of tree species, density, cover, and basal area. It also inlcuded planting of riparian tree poles and tree growth measurements at different locations in the irrigated corridor mirroring the percolation plot studies. A broad research effort included field measurement of components of the water budget for this valley. These measurements included ditch flows, groundwater water level changes, and river stage for river flow. Estimates from the literature were found for difficult to measure components such as mountain front recharge and ephemeral stream recharge, the latter of which was corroborated with field installation of crest gages in a major ephemeral stream. PARTICIPANTS: New Mexico State University. Sandia National Laboratories. New Mexico Acequia Association. Alcalde Acequia Association. Rio Arriba County. US Bureau of Reclamation. U. S. Geological Survey. NM Water Resources Research Institute. TARGET AUDIENCES: Land and water managers. Arid region hydrologists. Office of the State Engineer. Upper Rio Grande water management group. Small scale farmers. Local irrigation associations. Southwestern acequia groups. Agricultural, vadose zone, and ground water hydrologists. Individual irrigators. Community water groups. Local natural resource and conservation groups. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Changes in knowledge We used a combination of field measurements and modeling for determining different components of the water budget. Our results show that on average ditch flow is 0.9 cms, ditch seepage is 10%, irrigated field deep percolation is 30%, and ground water level rise is 0.4 m over the entire valley after the irrigation season started. We calculated that on average, 50% of the water diverted into the main irrigation ditch returns back to the river as surface return flow and about 10% of the total ditch inflow returns as groundwater flow. Results revealed a highly complex fluvial deposition environment that was challenging to model with one- and two-dimensional models. Results from this study show that a significant amount of water being diverted into the valley seeps from ditches and percolates below fields and resides in shallow groundwater for 1 to 3 months before returning to the river. This storage and release function provides water to the river in times of low flow and may save water on a regional basis by reducing evapotranspiration losses. Implications for climate change and land and water use changes will be the foci of future efforts, since the results suggest traditional irrigation systems may serve as very important systems to mitigate, dampen, and modulate variability and fluctuation in river flow, especially under future scenarios of reduced snow, increased rain, and earlier snowmelt runoff. Changes in actions Changed irrigation sytem management was identified. Based on study results, irrigators in the region have postponed, reanalyzed, and in at least one case cancelled projects to line irrigation ditches with concrete. Irrigated valley water budgets provided by this study have directly led to more informed agricultural water management . Changes in conditions There has been a new emphasis on hydrology study by irrigators in the study region. Local acequia associations, recognizing the importance of acequia hydrology, are seeking state support for new acequia hydrologist based in northern new mexico to broaden and expand on the work initiated in this study.
Publications
- Journal articles. 2008.
- Ochoa, C.G., A.G. Fernald, S.J. Guldan, and M.K. Shukla. 2009. Water movement through a shallow vadose zone--A field irrigation experiment. Vadose Zone Journal 8(2). (In press).
- Ochoa, C., A. Fernald, S. Guldan, V.C. Tidwell, J.P. King, Y. Cevik, C. Cusack. Surface Water and Ground Water Interactions In an Irrigated Valley in Northern New Mexico. 2008. Joint Annual Meeting GSA, SSSA, ASA, CSSA, GCAGS, HGS: Celebrating the International Year of Planet Earth. October 18-21, 2008, Houston, TX.
- Ochoa, C., A. Fernald, S. Guldan, V.C. Tidwell, J.P. King, Y. Cevik, C. Cusack. Surface Water and Ground Water Interactions In an Irrigated Valley in Northern New Mexico. 2008. American Geophysical Union Fall meeting. December 8-12, 2008, San Francisco, CA.
- Helmus, A.M., A.G. Fernald, D.M. VanLeeuwen, A.L.Ulery, T.T. Baker, and L.B. Abbot. 2009. Surface water irrigation input effects on shallow groundwater quality and recharge along the Rio Grande in Northern New Mexico. Journal of the American Water Resources Association. (In press)
- Abstracts. 2008.
- Ochoa, C., A. Fernald, S. Guldan, V.C. Tidwell, J.P. King, Y. Cevik, C. Cusack. 2008. Surface Water and Ground Water Interactions In an Irrigated Valley in Northern New Mexico. Eos Trans. AGU, 89(53), Fall Meet. Suppl., Abstract H21D-0851
- Newsletters. 2008.
- Calderon, L. 2008. NMSU student studies possible benefits of acequias. New Mexico Water Resources Research Institute. Newsletter Vol. XXXI No. 3. NMWRRI. Las Cruces, NM. July 2008.
- Professional meeting posters. 2008.
- Cusack, C. and Fernald A.G. 2008. Effects of acequias and groundwater levels on riparian vegetation, evapotranspiration, and restoration. New Mexico Water Resources Research Institute Technical Symposium. Soccoro, NM. August 15, 2008.
- Cusack, C., A. Fernald, and S. Guldan. 2008. Effects of Acequias and Groundwater Levels on Riparian Vegetation, Evapotranspiration, and Restoration. American Water Resources Association Summer Specialty Meeting; Riparian Ecosystems and Buffers: Working at the Waters Edge. Virginia Beach, VA. June 30-July 2, 2008.
- Fernald, A., Y. Cevik, C. Ochoa, C. Cusack. V. Tidwell, P. King, S. Guldan . 2008. Irrigation System Seepage Effects on River Floodplain Hydrology. CSREES -- National Water Conference. Sparks, Nevada. February 3-7, 2008.
- Ochoa, C.G., A.G. Fernald, S.J. Guldan, M.K. Shukla. Characterization of Water Movement through the Unsaturated Zone and Groundwater Response Following Flood Irrigation: A field study. 2008. Joint Annual Meeting GSA, SSSA, ASA, CSSA, GCAGS, HGS: Celebrating the International Year of Planet Earth. October 18-21, 2008, Houston, TX.
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Progress 09/15/06 to 09/14/07
Outputs
To identify the effects of acequia system seepage on groundwater and river flow, this study measures components of the Rio Grande floodplain water budget and integrates hydrologic fluxes with computer modeling. Field data collection for study of deep percolation and shallow groundwater level rise after flood irrigation in an sandy-loam soil alfalfa-grass field was concluded in November of 2007. Previous results showed that deep percolation below the upper 1-m root zone ranged from 15% to 60% and that there was a water level rise of up to 38 cm. The antecedent soil moisture and the amount of water applied greatly influence percolation and groundwater response. Concurrent study in an clay and sandy clay soil apple orchard showed 14% to 42% deep percolation below the 1-m root zone and water level rise of up to 30 cm. A manuscript based on the study will be submitted for publication in 2008. An experiment was established to link the continuum of water movement through the
entire unsaturated zone and the shallow groundwater response following flood irrigation. Pairs of 12 m by 12 m experimental plots were installed in each of three soil types that account for about 85% of the soils in the entire study agricultural corridor. The plots were instrumented with soil moisture sensors, soil temperature sensors, and wells with pressure transducers to determine the wetting front arrival time, water flux at different soil depths, and water table response. Preliminary results showed the amount of irrigation water applied, antecedent soil moisture, soil layering, and depth to water table were important in water transport through the vadose zone and in water level response to flood irrigation. Field observations are providing inputs to Hydrus-1d flow modeling. A manuscript based on project results will be submitted to the Vadose Zone Journal in February of 2008. Ditch rating curves used with ditch stage data were collected hourly in three different stilling wells
equipped with pressure transducers. were used with stage data to obtain ditch inflow and outflow. These inflow-outflow calculations allowed determination of water diversion amount, presumably for agricultural use, from the main irrigation ditch. River-stage data are also being collected on an hourly basis. Flow was measured synoptically in all ditches in the Alcalde Valley to show relative flow between the 9 different ditches. Approximately 60 wells, including experimental and domestic wells, in the entire valley have been equipped with pressure transducers to monitor water table fluctuations all year around. Water level data is being collected hourly and will help us to construct water table maps for different water inputs-outputs, for example during and off the irrigation season. Data from over 800 existing wells was used to construct a geophysical model of the Alcade Valley. This work will form the basis of a publication to be submitted in 2008. A MODFLOW groundwater model to
characterize groundwater flow and interactions with surface water was largely parameterized. It is expected that the model will be completed and ready for calibration in early 2008.
Impacts
Through studying surface water-groundwater interactions in acequia-irrigated floodplains in north-central New Mexico, we are developing an understanding of the complexity of the hydrological system of the upper Rio Grande Basin that will help stakeholders make informed decisions. We've looked at ditch-seepage, the hydrology of the shallow groundwater and seepage impact on water quality. Currently we are looking at the integrated floodplain hydrology for sustainable agriculture and healthy ecosystems in river valleys of water-scarce regions. We have found that there are important issues people need to consider before they change how they manage the water in the Rio Grande Basin. The project has gained considerable interest and support among irrigation water users and managers in New Mexico. This is exemplified by a resolution being submitted and passed at the 8th Annual Congreso de las Acequias, in Santa Fe, NM, indicating their interest in and support for the
continuation of the research forwarded by this grant project. This group represents the community irrigation ditches in the state. The entire project and different components of it have been presented in several scientific meetings to different groups of people. Considerable interest by some of these groups has resulted in different schemes of collaboration, for example, project investigators have been invited to submit a manuscript to an especial issue in the Vadose Zone Journal based on a presentation given at the Unsaturated Zone Interest Group (UZIG) Meeting in August 27-30, 2007 in Los Alamos, NM.
Publications
- Ortiz, M., C. Brown, A. Fernald, T.T. Baker, B. Creel, and S. Guldan. 2007. Land use change impacts on Acequia water resources in northern New Mexico. Journal of Contemporary Water Research & Education 137:47-54.
- Ochoa, C.G., A.G. Fernald, S.J. Guldan, and M.K. Shukla. 2007. Deep percolation and its effects on shallow groundwater level rise following flood irrigation. Transactions of the ASABE 50(1):73-81.
- Fernald, A.G., T.T. Baker, and S.J. Guldan. 2007. Hydrologic, riparian, and agroecosystem functions of traditional acequia irrigation systems. Journal of Sustainable Agriculture 30(2):147-171.
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