What percent of Tantallon is impervious?

There is not a County rating (see state): https://infrastructurereportcard.org/wp-content/uploads/2021/07/Maryland-ASCE-Report-Card-2020-Full-Sections.pdf

DoE operates and monitors rainfall (precipitation) gauges in the Anacostia River and Western Branch Watersheds which fall in the north and central County. The nearest County operated gauge to Ft. Washington is at Water Street in Upper Marlboro. Private entities like Weather Underground and Weather Bug collect rainfall data in the Ft. Washington area.

EPA establishes national ambient air quality standards (NAAQS) for six common air pollutants - carbon monoxide, lead, ground-level ozone, particulate matter, nitrogen dioxide, and sulfur dioxide. (Awaiting MWCOG confirmation of the status of (non)attainment status for Washington metropolitan region).

The infrastructure is built with the communities. It ranges in ages from approximately 70 years old to as recent as a few years old. There is not a set schedule (i.e., bridges or SWM facilities) but the County inspects approximately every 5-10 years. Developers are required to inspect all systems that they tie into.

The County is under a consent agreement from MDE/EPA to provide a designated number of acres of treatment for impervious surfaces not controlled by BMPs.

To the extent that we know, there are no specific State/Federal non-compliance issues identified for Swan Creek/Tantallon.

There is not an individual breakdown per County.

Click the link to access the map that identifies existing BMPs in the Swan Creek/Tantallon watershed demonstrating WQ and volume controls. https://www.arcgis.com/apps/webappviewer/index.html?id=dc168a43d3554905b4e4d6e61799025f

The County is not required to provide water quality tests at the creek level. It is tested at the watershed level (i.e.: Potomac River)

The County is not required to provide water quality tests at the creek level. It is tested at the watershed level (i.e.: Potomac River)

The County’s geographical area is approximately 490 square miles; Impervious is 48 Sq. Mi. = 9.8%

The standard depends on when it was developed. Portions of the community were developed prior to many of the stormwater regulations that exist today. The current County Standards can be found in the Drainage Design Manual. https://www.princegeorgescountymd.gov/DocumentCenter/View/4782/Stormwater-Management-Design-Manual-PDF?bidId=

Click the link to view the map identifying existing BMPs in the Swan Creek/Tantallon watershed demonstrating WQ and volume control. BMP’s (referring to Stormwater Management BMP’s) can be found on the following map through the Department of the Environment. https://www.arcgis.com/apps/webappviewer/index.html?id=dc168a43d3554905b4e4d6e61799025f

The Noon Property is near Avalon ES (7302 Webster Ln, Fort Washington, MD 20744). It is owned by PGCPS and used for off-site tree preservation credits. (When we take down trees on one site, we have the option of preserving, in perpetuity, trees on another site that would otherwise have been developed.)

See response to Question 9. There are many different sources of rain gauge data. Here are several options:

https://water.weather.gov/ahps/

https://www.wunderground.com/