HR: 0830h
AN: H51C-1064    [PDF]
TI: Developing Water Quality Management Strategies At Different Watershed Scales Using System Dynamics Simulation
AU: * Tangirala, A
EM: tangirala@uky.edu
AU: Teegavarapu, R
EM: ramesh@engr.uky.edu
AU: Ormsbee, L
EM: lormsbee@engr.uky.edu
AB: System Dynamics simulation is used for developing models to understand the fate and transport of pathogens at different watershed scales. The models are developed using an object-oriented modeling environment to simulate and analyze water quality management strategies for pathogen impaired streams. The main objective of this work is to evaluate the relative contributions of pathogen loads from each watershed to facilitate the budget allocations that have to be made in each watershed and also to understand the fate and transport of pathogens in impaired streams of each watershed. The models can be used to generate several management scenarios and evaluate several adaptive management alternatives that are designed to reduce further impairment. An object-oriented simulation environment, conceived on the principles of system dynamics (SD) is used for the development of the model. Two important generic building blocks, stocks and flows that are part of the simulation environment are used to model various elements that govern the water bodies and pollutant loadings. The modeling process consists of developing, stock-flow diagrams and finally carrying out computer simulations using difference equations to integrate stocks and flows. The model structure and behavior of the system is validated using dimensionality, replication and sensitivity tests; and calibration along with validation is carried out using appropriate model performance measures. Case study application of this concept is illustrated by developing simulation models for pathogen impaired streams in the three watersheds, North Fork, Upper Cumberland and Big Sandy in southeastern region of Kentucky, USA. Straight pipes and failing septic systems have been identified to be the major sources of pathogen impairment in these watersheds and therefore are key factors influencing management alternatives. Preliminary results suggest that the fate and transport process of pathogens in a river system and at a larger watershed scale can be simulated using simple object-oriented simulation models under data-sparse conditions. The model helps the user to separate policy questions from the data and provides the facility to generate "what-if" scenarios while keeping the modeling process transparent.
DE: 1871 Surface water quality
SC: Hydrology [H]
MN: 2003 Fall Meeting