StreamStats in Massachusetts

New peak-flow regression equations were made available in StreamStats version 3 for Massachusetts on May 12, 2017 and in version 4 on June 14, 2017. The new equations can be used for estimating the 50-, 25-, 10-, 2-, 1-, 0.5, and 0.2-percent annual exceedance probabilities (Zarriello, 2017). StreamStats for Massachusetts also can be used to estimate the long-term 99-, 98-, 95-, 90-, 85-, 80-, 75-, 70-, 65-, 60-, 55-, and 50-percent duration flows, the 7-day, 2-year and the 7-day, 10-year low flows, and the August median flow for ungaged sites (Ries and Friesz, 2000). The application also includes an equation for estimating the probability of a stream flowing perennially (Bent and Steeves, 2006), and equations for estimating bankfull geometry—width, mean depth, cross-sectional area – and bankfull discharge (Bent and Waite, 2013). The reports below present the equations used to estimate the statistics, describe the errors associated with the estimates, and describe the methods used to develop the equations and to measure the basin characteristics used in the equations. Users should familiarize themselves with the report before using StreamStats to obtain estimates of streamflow statistics for ungaged sites.

The equations from each report are applicable for most areas of Massachusetts except eastern Buzzards Bay, Cape Cod, and the Island regions, and the main branches of the Connecticut and Merrimack Rivers. Estimates obtained from the equations assume natural flow conditions at the site.

For the equations from Ries and Friesz (2000), StreamStats reports the uncertainty of the estimates for basins with drainage areas between 1.61 and 149 square miles. For equations from Bent and Steeves (2006), StreamStats reports the uncertainty of the estimates for basins with drainage areas between 0.01 and 1.99 quare miles. For the equations by Bent and Waite (2013) StreamStats reports the uncertainty of the bankfull estimates for basins with drainage areas between 0.60 to 329 square miles. For the equations by Zarriello (2017), StreamStats reports the uncertainty of estimates for basins with drainage areas between 0.16 to 512 square miles. Errors for basins with drainage areas beyond these bounds are unknown. The prediction intervals that are presented for the bankfull estimates were determined using equations that differ from those used by Bent and Waite (2013), and as a result, the presented prediction intervals are substantially wider than the actual intervals. Limited trials indicate differences in prediction intervals of between 30 and 90 percent.

The Massachusetts Sustatinable Yield Estimator version 2.0 (MA SYE) was developed to be used in conjunction with the Massachusetts StreamStats application to estimate daily unaltered and water-use adjusted streamflow at ungaged locations in Massachusetts for the period of October 1, 1960 to September 30, 2004.  Basin delineations, basin characteristics, and aggregated water use information for the period of 2010-2014 can be obtained in the Massachusetts Streamstats application and imported into the MA SYE software.

General information and documentation of methods used in the MA SYE can be found at the following links:

The MA SYE software can be downloaded here:

Click on this link to obtain general information on the Massachusetts application, as well as specific sources and computation methods for basin characteristics.

StreamStats for Massachusetts was developed in cooperation with the Massachusetts Department of Conservation and Recreation, the Massachusetts Department of Environmental Protection, the Massachusetts Geographic Information System, and the Massachusetts Environmental Trust.

Link to Department of Conservation and RecreationLink to the Massachusetts Department of Environmental ProtectonLink to Massachusetts Geographic Information SystemLink to Massachusetts Environmental Trust