Joshua Smith, with Hanover Engineering, presented a look at the township’s MS4 plan during the East Allen Township Board of Supervisors meeting Feb. 13.

MS4 - Municipal Separate Storm Sewer System - is a statewide program to control stormwater runoff and pollution in streams.

The project classifies areas using a moniker for Hydraulic Unit Codes. The series 12 codes are for local areas that identify tributary systems. All the areas in East Allen Township are HUC-12 areas.

There are three watersheds in East Allen - Catasauqua Creek, Monocacy Creek and the east branch of Monocacy Creek. Within the three watersheds are urbanized areas as well as rural lands.

The areas incorporated in the proposal include 36 discharge points that drain 2-plus square miles. The land uses are primarily cropland and the high-density mixed urban areas.

For this five-year project period, 2019-24, the requirement is to reduce pollution by 10 percent. The primary pollutant in the township is sediment. The goal is to reduce sediment by 162,000 pounds per year across the three watersheds. The watershed details are shown on the township’s website, eatwp.org, as an appendix to the Hanover Engineering report.

Soils in the area are mostly limestone with shale and are considered well drained.

Stormwater is discharged into the creeks, which then flow to the Lehigh River and eventually into the Delaware River. Local creeks are deemed high-quality waterways, with the only caution being natural pathogens. Lehigh and Delaware rivers are classified as impaired because of silting. The Delaware River has mercury warnings.

Two projects in the township were included in new developments built in the past decade. One reduces sediment load by 562 pounds across a drainage area of 3.6 acres; the other removes 9,790 pounds with a drainage area of 110 acres.

The details show 10 projects planned in the Catasauqua Creek watershed that can reduce 770,000 pounds of sediment when fully implemented. The east branch of the Monocacy Creek has five potential projects. Monocacy Creek has four projects.

East Allen Township is entering into planning and permitting to move the projects forward. The goal is to meet or exceed the requirements for the five-year permit period. The township agreed to pursue grants to implement the plan and indicated that fee revenues may be used as matching funds for the grants.

The plan was on the website for the required open period, but there were no comments from the public.