Modeling non-point source pollution in surface water under non-stationary climates and land uses
| Main Author: | |
|---|---|
| Language: | English |
| Published: |
The Ohio State University / OhioLINK
2014
|
| Subjects: | |
| Online Access: | http://rave.ohiolink.edu/etdc/view?acc_num=osu1408983669 |
| id |
ndltd-OhioLink-oai-etd.ohiolink.edu-osu1408983669 |
|---|---|
| record_format |
oai_dc |
| spelling |
ndltd-OhioLink-oai-etd.ohiolink.edu-osu14089836692021-08-03T06:27:12Z Modeling non-point source pollution in surface water under non-stationary climates and land uses Browning, Drew Civil Engineering Environmental Engineering SWAT non point source nitrogen hydrologic modeling Non-point source (NPS) pollution causes widespread impairment to surface water in the United States and can potentially impact human health and safety. Nutrient NPS pollution from agriculture is one of the most damaging and widespread non-point source problems in surface water. Due to the complexity of the processes that govern it, the spatial and temporal extent of nutrient NPS pollution can be difficult to assess and quantify. The use of physically based computer modeling allows us to represent the various physical and chemical cycles that control the amount of pollutant loading that ultimately ends up in a stream. A simulation of the Upper Big Walnut Creek (UBWC) watershed in central Ohio was set up using the Soil and Water Assessment Tool (SWAT) 2012 model and the ArcSWAT GIS interface. Calibration was performed for the portion of the watershed above the USGS stream gauge 03228300 and calibrated parameters were extended to the entire watershed. The simulation was calibrated for 2000-2004 and validated for 2005-2009 with prediction efficiencies of 0.62 and 0.74, respectively. Four sets of experiments were performed. The first of these, a sensitivity analysis, was undertaken to understand the influence of selected SWAT variables and their assumptions on the watershed’s hydrologic and nutrient cycles. The other sets of experiments examined the effects of climate change, agricultural management change, and the combination thereof on the UBWC. Climate change simulations used input downscaled from output of the Climate Model Intercomparison Project (CMIP5) multi-model dataset. This input consisted of two climate scenarios representing different emissions pathways for 2006-2100, downscaled with quantile mapping and regression techniques. The agricultural management change experiments used a stationary climate in conjunction with four scenarios representing potential avenues of change within the UBWC. These included a reference scenario reflecting the watershed’s current management, a reference scenario with cover crops, a cash grain rotation scenario, and a cash grain rotation scenario with cover crops. Lastly, coupled management change/climate change simulations were performed. The management component of these simulations used the four scenarios previously developed. Climate change was simulated using the SWAT built-in weather generator as a source of weather inputs. The statistics used to run the weather generator were calculated from the quantile mapping downscaled input used in the first climate change experiment.Downscaled Representative Concentration Pathway (RCP) 4.5 and RCP 8.5 climate scenarios both predict increased temperatures throughout the year and increases to early spring precipitation. As a result of the temperature increases, crop planting and harvest dates occur earlier in the year, shifting the watershed hydrologic cycle. Residue mineralization, tile nitrogen, and sediment losses are also affected. Overall, climate change was found to reduce NPS pollution loading, however, decreases in streamflow may negate these reductions by increasing the concentration of NPS pollutants. Management practices such as the changes in rotation and application of cover crops studied may also become necessary to ensure protection of human health and the environment. 2014 English text The Ohio State University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=osu1408983669 http://rave.ohiolink.edu/etdc/view?acc_num=osu1408983669 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws. |
| collection |
NDLTD |
| language |
English |
| sources |
NDLTD |
| topic |
Civil Engineering Environmental Engineering SWAT non point source nitrogen hydrologic modeling |
| spellingShingle |
Civil Engineering Environmental Engineering SWAT non point source nitrogen hydrologic modeling Browning, Drew Modeling non-point source pollution in surface water under non-stationary climates and land uses |
| author |
Browning, Drew |
| author_facet |
Browning, Drew |
| author_sort |
Browning, Drew |
| title |
Modeling non-point source pollution in surface water under non-stationary climates and land uses |
| title_short |
Modeling non-point source pollution in surface water under non-stationary climates and land uses |
| title_full |
Modeling non-point source pollution in surface water under non-stationary climates and land uses |
| title_fullStr |
Modeling non-point source pollution in surface water under non-stationary climates and land uses |
| title_full_unstemmed |
Modeling non-point source pollution in surface water under non-stationary climates and land uses |
| title_sort |
modeling non-point source pollution in surface water under non-stationary climates and land uses |
| publisher |
The Ohio State University / OhioLINK |
| publishDate |
2014 |
| url |
http://rave.ohiolink.edu/etdc/view?acc_num=osu1408983669 |
| work_keys_str_mv |
AT browningdrew modelingnonpointsourcepollutioninsurfacewaterundernonstationaryclimatesandlanduses |
| _version_ |
1719437001720070144 |