Study and analysis of the water quality of the Blackstone River watershed

Shahriar Mahbub Alam, University of Rhode Island

Abstract

Wet weather water quality of the Blackstone River was analyzed. Three wet weather events were successfully captured for the wet weather program. The concentrations, EMCs (event mean concentration) and EMMs (event mean mass) for different constituents were determined. Net gains and losses per reach were calculated and major point and non point sources were compared. The ranking for each storm was calculated for both wet and total loads. A comparison of wet and dry weather sources for different constituents was provided. A procedure was developed to separate runoff and resuspension. An estimate of annual loadings at the MA/RI state line and end of river (to Narragansett Bay) was provided.^ The analysis of the concentration data showed that wet weather did impact the water quality of the Blackstone River. For UBWPAD there was no violation of maximum ammonia discharge during dry weather conditions but violations did occur in two out of three storms during wet weather. During peak flow fecal coliforms from Worcester passed by UBWPAD without instream disinfection. This was due to the higher flows at the WWTF and the lower chlorine residual concentrations.^ Wet weather did cause acute criteria violations. During the height of the storm, instream hardness dropped resulting in lower acute criteria concentrations. The cause of higher metal concentration may be resuspension of the bottom sediments due to high flow and velocity, runoff, or poor performance of treatment facilities subjected to increased flow during the storm.^ A relationship was developed between rainfall and wet loadings using the data collected during the three storms and previous wet weather data available for the state line and end of river. These equations were used to estimate the annual wet loading rates for the Blackstone River.^ The dry weather models were used to estimate baseline mass loadings under steady state flow. The relationships were developed and used to estimate the annual dry weather contributions at MA/RI state line (BWW13) and end of the river (BWW21). These dry weather loadings can be compared with the annual wet weather loadings. In the long run this is exactly what is needed to allow decisions into pollutant control. ^

Subject Area

Hydrology|Engineering, Civil|Engineering, Sanitary and Municipal

Recommended Citation

Shahriar Mahbub Alam, "Study and analysis of the water quality of the Blackstone River watershed" (1996). Dissertations and Master's Theses (Campus Access). Paper AAI9723551.
http://digitalcommons.uri.edu/dissertations/AAI9723551

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