Applying unit hydrograph concept to predict pollutant loads of stormwater runoff delivered from urban source area

摘要

Examining the delivery of urban rainfall-runoff pollutants are important to quantify pollutant loads to receiving waters, drainage system appurtenances, and unit operations as well as guiding maintenance practices and regulation. This study has utilized unit hydrograph (UH) and instantaneous unit hydrograph (IUH) concepts to predict the pollutant loads in stormwater runoff delivered from three urban catchments. This study first hypothesizes that a single yield function may be developed on a catchment basis to describe the yield of each pollutant (particulate matter [PM] or metals, etc.) irrespective of whether the event is classified as flow- or mass-limited. Hypothesis testing is conducted on an event basis for pollutant load transport from three monitored source area catchments. Hydrologic and pollutant transport are examined by unit-graphs (hydrograph and pollutograph) derived from intra-event measurements for each catchment. From the median IUH and instantaneous unit pollutograph (IUP) and corresponding UH and unit pollutograph (UP) developed for each catchment, pollutographs are generated by convolution of the UH and UP to reproduce measured event-based pollutant loads. Results illustrate the feasibility of using the UH/IUH and UP/IUP to predict event-based pollutant loads delivery from small urban catchments. (c) 2018 American Institute of Chemical Engineers Environ Prog, 38: 435-444, 2019