A Numerical Modeling Assessment of the Influences of Human Impacts and Natural Conditions on Low Dissolved Ozygen and Control of Watershed Runoff in the Unnamed Tributary to Pitts Creek, Virginia
Upper tributaries of tidal creeks on Virginia’s Eastern Shore are increasingly affected by anthropogenic activities such as agricultural practices. During the summer, low dissolved oxygen (DO) was frequently observed in the Unnamed Tributary to Pitts Creek, a small creek on the Eastern Shore of Virginia. Although being mainly surrounded by forest and agricultural land, the Creek also has a large wetland adjacent to it. As having been altered by human development in recent years, it receives discharges from adjacent farmlands through drainage ditches. Thus, the Creek is potentially threatened by nutrient enrichment. On the other hand, the light condition in the Creek appears unfavorable for algae growth and may alleviate the consequence of eutrophication. In order to understand the contributions of human impacts and natural conditions on low DO, a linked watershed and in-stream eutrophication model was used to simulate and diagnose DO dynamics in the system. The model results revealed that both human impacts and natural conditions contribute to low DO in the Creek. While accumulative deposition of organic carbon from both in-situ production and runoff from ambient watershed (especially from the surrounding wetland) resulted in high SOD in the Creek, high temperature and poor surface reaeration aggravated low DO in the system. To eliminate low DO, improvement of physical conditions of the Creek should be considered in addition to nutrient reduction. The modeling practices indicate that the linked watershed and in-stream modeling approach is a suitable tool for managing nutrient sources in the watershed.
dissolved ozygen human impacts natural conditions watershed model eutrophication model
SHEN Jian ZHAO Yuan WANG Taiping
Department of Physical Sciences,Virginia Institute of Marine ScienceCollege of William and Mary,Glou Department of Physical Sciences,Virginia Institute of Marine Science College of William and Mary,Glo
国际会议
2009 International Symposium on Environmental Science and Technology(2009环境科学与技术国际会议)
上海
英文
587-593
2009-06-02（万方平台首次上网日期，不代表论文的发表时间）