Integrated Modular Modeling of Water and Nutrients From Point and Nonpoint Sources in the Patuxent River Watershed¹

Abstract

We present a simple modular landscape simulation model that is based on a watershed modeling framework in which different sets of processes occurring in a watershed can be simulated separately with different models. The model consists of three loosely coupled submodels: a rainfall-runoff model (TOPMODEL) for runoff generation in a subwatershed, a nutrient model for estimation of nutrients from nonpoint sources in a subwatershed, and a stream network model for integration of point and nonpoint sources in the routing process. The model performance was evaluated using monitoring data in the watershed of the Patuxent River, a tributary to the Chesapeake Bay in Maryland, from July 1997 through August 1999. Despite its simplicity, the landscape model predictions of streamflow, and sediment and nutrient loads were as good as or better than those of the Hydrological Simulation Program-Fortran model, one of the most widely used comprehensive watershed models. The landscape model was applied to predict discharges of water, sediment, silicate, organic carbon, nitrate, ammonium, organic nitrogen, total nitrogen, organic phosphorus, phosphate, and total phosphorus from the Patuxent watershed to its estuary. The predicted annual water discharge to the estuary was very close to the measured annual total in terms of percent errors for both years of the study period (£2%). The model predictions for loads of nutrients were also good (20-30%) or very good (<20%) with exceptions of sediment (40%), phosphate (36%), and organic carbon (53%) for Year 1.

Using Multiple Watershed Models to Predict Water, Nitrogen, and Phosphorus Discharges to the Patuxent Estuary1

“…Smithsonian Environmental Research Center Landscape Smithsonian Environmental Research Center Landscape (SERCLM) is a modular simulation model of the Patuxent watershed that was developed to generalize the analysis and application of the SERC model (described above) beyond the 2‐year time domain and Patuxent only spatial domain of the SERC model. The SERCLM model includes three sub‐components (Liu and Weller, 2008; Liu et al. , 2008).…”

“…Finally, a stream routing model (Liu and Weller, 2008) combines the predicted discharges from the 210 watersheds with monitored data on reservoir and point source discharges, and then routes water and nutrients to the estuary while also accounting for nutrient uptake during transport. The stream routing parameters were calibrated manually (Liu and Weller, 2008; Liu et al. , 2008) to achieve the best match of streamflow, TN, and TP concentrations from SERC and USGS monitoring stations (described earlier).…”

Evaluation of the CRU TS3.1, APHRODITE_V1101, and CFSR Datasets in Assessing Water Balance Components in the Upper Vakhsh River Basin in Central Asia

“…Similarly, previous studies on the applicability of models to estimate hydrological components in the highlands of Tajikistan (UVRB) in Central Asia have not been conducted. Various hydrological models at the watershed scale have been used for the estimation of water cycle components, including the Hydrologic Engineering Center hydrologic modeling system [4], MIKE SHE [5], the soil and water assessment tool [6], the hydrologic simulation program Fortran [7], and the snowmelt runoff model [2]. The SWAT model is internationally recognized as a robust hydrological model and is widely used, including in several basins that have snowmelt-dominated streamflow [8][9][10][11][12][13][14].…”

Status Mutu Air pada Lahan Gambut di Sungai Putat Kota Pontianak Kalimantan Barat

“…Keberadaan sungai sebagai air permukaan sangat diperlukan bagi kelangsungan kehidupan manusia, antara lain sebagai air baku minum, air baku irigasi pertanian, peternakan, pembangkit listrik, rekreasi, dan sebagainya. Oleh karena itu sudah selayaknya diberikan perhatian yang cukup besar terhadap sungai, khususnya dalam menjaga kualitasnya agar tetap dapat digunakan secara layak dan berkelanjutan (Liu, Zhi Jun, Wller, Donald E., Jordan, Thomas E., Correll, David L., Boomer, 2008). Namun demikian, banyak sungai besar di dunia yang telah tercemar akibat aktivitas manusia (anthropogenic) (Hendrawan, 2005 Tindakan sederhana yang bisa dilakukan untuk mengendalikan tingkat pencemaran sungai adalah melakukan monitoring secara kontinu.…”