|Quyang, Ying - Us Forest Service (FS)|
|Paz, Joel - Mississippi State University|
Submitted to: Water Resources Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/20/2017
Publication Date: N/A
Interpretive Summary: With increased interest in conservation farming, more irrigation farm ponds have been constructed in recent years both in the Mississippi Delta and Blackland Prairie regions of Mississippi. In order to use water responsibly and profitably for irrigation, it is important that farm pond capacity is sufficient to meet crop water use requirements, which vary with crop species, seasons, soil, hydrological conditions, and climate environments. However, the hydrological processes, water budget, and environmental benefits and consequences of the ponds in Mississippi are yet to be fully quantified and exploited. A team of scientists used the commercially available STELLA (Structural Thinking and Experiential Learning Laboratory with Animation) software to develop a computer simulation model that would estimate farm pond hydrological processes and water budgets in Mississippi. The model was tested for accuracy using existing experimental measurements taken in the Mississippi Delta. A simulation scenario was then performed to estimate the diurnal and seasonal pond hydrological processes and water budget under natural field conditions at Metcalf Farm in Porter Bayou Watershed. Results suggest the STELLA model should be a powerful tool for estimating irrigation pond water budget (inputs and outputs) both diurnally and seasonally. The research team plans to link the model with on-farm irrigation practices and crop water uses, in order to determine if the model can provide a guide to farmers on how much water is available for crop irrigation. Data on field hydrology and other model outputs are available for rigorously calibrating and validating the model at the Metcalf Farm, but such data are not yet available for an experimental site in the Blackland Prairie region of east central Mississippi.
Technical Abstract: With increased interest to conserve groundwater resources without adversely affecting crop yield potential, more irrigation farm ponds have been constructed in recent years in Mississippi. However, the hydrological processes, water budget, and environmental benefits and consequences of these ponds have not yet been fully quantified. This study developed a computer model to estimate farm pond hydrological processes and water budgets in Mississippi using the STELLA (Structural Thinking and Experiential Learning Laboratory with Animation) software. Two simulation scenarios were chosen in this study, one was to estimate the diurnal and seasonal pond hydrological processes and water budget at Metcalf Farm (33o 39' 48" N; 90o 39' 12"W) located in Porter Bayou Watershed in Mississippi Delta without pumping pond water for crop irrigation, while the other was to evaluate the pond water availability for soybean irrigation. Simulations showed evaporative water loss from the pond was minimal, while runoff water from rainfall was a major source of water entering into the pond. Therefore, factors that would affect surface water runoff should be considered in locating and sizing a farm pond in Mississippi. The seasonal rainwater and runoff water collected by the pond was: winter > spring > summer > fall, which corresponded well to the seasonal rainfall events; whereas seasonal order of pond evaporation was: summer > spring > fall > winter, which corresponded well to the seasonal solar radiation and air temperature. Our simulations further revealed that the ratio of pond size to soybean irrigation area was 1:7. That is, every 1-ha pond with a depth of 1.8 m can supply sufficient water to 7 ha of land in soybean production in Mississippi Delta. The STELLA model developed in this study proved to be a useful tool for estimating pond water budget, and consequently irrigation practices for summer crops.