Investigation and modeling of land use effects on water quality in two NYC water supply streams.

The paired watershed monitoring approach is widely used to investigate hydrologic processes and water quality, providing streamflow and water quality records for long-term trend analysis, as well as data for developing and testing hydrologic models. In this study we use 20 years of streamflow and water quality data, along with a watershed model, to examine sources of stream nutrients and their changes over time in two small streams within the New York City water supply system. We compare sources and trends in stream nitrate and dissolved phosphorus in the urbanized Amawalk watershed with those of the predominantly forested Boyd Corners watershed in the Croton system of reservoirs.

Impact of storm events on disinfection byproduct precursors in a drinking water source in the Northeastern United States.

Storm events play a crucial role in organic matter transport within watersheds and can increase the concentration and alter the composition of NOMs and DBP formation potential. To assess the impact that storm events can have on drinking water quality, samples were collected and analyzed across four storm events in the Neversink River, Catskill region, New York in 2019 and 2022. Source water natural organic matter (NOM) was characterized, and the change of NOM quality was evaluated due to storm impacts.

Integrating terrestrial and aquatic processes toward watershed scale modeling of dissolved organic carbon fluxes.

Dissolved organic carbon (DOC) is not only a critical component of global and regional carbon budgets, but also an important precursor for carcinogenic disinfection byproducts (DBP) generated during drinking water disinfection process. The lack of process based watershed scale model for carbon cycling has been a limiting factor impeding effective watershed management to control DOC fluxes to source waters. Here, we integrated terrestrial and aquatic carbon processes into the widely tested Soil and Water Assessment Tool (SWAT) watershed model to enable watershed-scale DOC modeling (referred to as SWAT-DOC hereafter).

Using detailed monitoring data to simulate spatial sediment loading in a watershed.

The use of watershed models as cost-effective tools to quantify the impact of conservation practices on water quality is often constrained by lack of data for model parameterization. This study uses short-term (3 years) detailed monitoring data to guide spatially distributed model parameterization and modeling analysis for suspended sediment in the Upper Esopus Creek Watershed (UECW) that is part of the New York City water supply. The calibrated Soil and Water Assessment Tool (SWAT) model simulated suspended sediment loading from tributary sub-basins and at the watershed outlet that were comparable to field measurements.

Predicting trihalomethanes in the new york city water supply.

Chlorine, a commonly used disinfectant in most water supply systems, can combine with organic carbon to form disinfectant byproducts, including carcinogenic trihalomethanes. We used water quality data from 24 monitoring sites within the New York City water supply distribution system, measured between January 2009 and April 2012, to develop an empirical model for predicting total trihalomethane (TTHM) levels. Terms in the model included the following water quality parameters: total organic carbon, pH, water age (reaction time), and water temperature.