Revision History for Scientific Investigations Report 2008–5132

Carl S. Carlson, Leslie A. DeSimone, and Peter K. Weiskel

Simulated Effects of Year 2030 Water-Use and Land-Use Changes on Streamflow near the Interstate-495 Corridor, Assabet and Upper Charles River Basins, Eastern Massachusetts

-----------------------------------------------------

Posted online January 8, 2009

-----------------------------------------------------

Revised January 12, 2009. This addendum is to be added to the last paragraph of the abstract on page 1 of the report.

The potential effects of sewer-line extension and low-impact development on streamflows were also simulated in selected subbasins of the Assabet River Basin. The result of extending sewer lines with a corresponding decrease in septic-system return flow caused simulated September streamflows to decrease as much as 15 percent in the Fort Pond Brook subbasin. The effect of low-impact development (as defined in this study) was simulated in the Hop Brook subbasin in areas projected for commercial development.

In this simulation, the larger the area where low-impact development practices were applied, the less was the overall effect of development on recharge and nonstorm streamflow, compared to the effects of traditional commercial development Finally, simulated mean monthly streamflows per unit basin area, in cubic feet per second per square mile, were provided for all subbasins for both the base case and 2030 scenarios. Model results were expressed in this form to facilitate use of previously published methods for establishing streamflow requirements for habitat protection.