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Total Maximum Daily Load Criteria Assessment Using Monitoring and Modeling Data
Author(s) -
Keisman Jeni,
Shenk Gary
Publication year - 2013
Publication title -
jawra journal of the american water resources association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.957
H-Index - 105
eISSN - 1752-1688
pISSN - 1093-474X
DOI - 10.1111/jawr.12111
Subject(s) - linear regression , environmental science , scale (ratio) , water quality , regression analysis , computer science , regression , statistics , mathematics , ecology , physics , quantum mechanics , biology
Applications of Total Maximum Daily Load ( TMDL ) criteria for complex estuarine systems like C hesapeake B ay have been limited by difficulties in estimating precisely how changes in input loads will impact ambient water quality. A method to deal with this limitation combines the strengths of the C hesapeake B ay's Water Quality Sediment Transport Model ( WQSTM ), which simulates load response, and the C hesapeake B ay Program's robust historical monitoring dataset. The method uses linear regression to apply simulated relative load responses to historical observations of water quality at a given location and time. Steps to optimize the application of regression analysis were to: (1) determine the best temporal and spatial scale for applying the WQSTM scenarios, (2) determine whether the WQSTM method remained valid with significant perturbation from calibration conditions, and (3) evaluate the need for log transformation of both dissolved oxygen ( DO ) and chlorophyll a ( CHL ) datasets. The final method used simple linear regression at the single month, single WQSTM grid cell scale to quantify changes in DO and CHL resulting from simulated load reduction scenarios. The resulting linear equations were applied to historical monitoring data to produce a set of “scenario‐modified” DO or CHL concentration estimates. The utility of the regression method was validated by its ability to estimate progressively increasing attainment in support of the 2010 C hesapeake B ay TMDL .