This cache's goal is to provide a brief history of the environment in this area, a lesson on how important this area is, and to enjoy your trip. Keep your eyes open for wildlife. I've spotted herons, a big fox, and a turtle in my middle of winter visits. As this is a Fairfax County Park, make sure you observe park hours and rules (no night caching!)
History: The Brookfield Community Park is just over 25 acres and was constructed in the late 1950's as a community amenity. The pre-existing dam was originally constructed in the 1960’s and was rehabilitated in 1982. Since that time the dam embankment became overgrown with woody vegetation, the concrete spillway had become undermined and there was significant seepage through the earth embankment. The dam embankment was in poor condition and thought to be at risk for failure. Its new configuration drains the surrounding 49 acres and contributes to improved water quality downstream. Several divisions of DPWES and the Fairfax County Park Authority worked together to restore the dam in the Brookfield Park and create a habitat that is planted with native vegetation that provides water quality benefits and food, shelter and breeding grounds for the animals that live there.
Recognition: The Brookfield Park won 2nd place in the 2014 BUBBA awards. (Best Urban BMP in the Bay Award) contest sponsored by the Chesapeake Stormwater Network.
The lesson: The dam was rehabilitated to meet up-to-date safety and design standards. The dam and outlet structure were reconstructed and a wetland forebay system was installed.
Forebays are smaller ponds that are placed along the water flow path that collect and filter pollutants and control algae problems in the pond. Floating wetlands were installed to increase pollutant removal. These are constructed using native and aquatic plants that float in rafts and function as natural wetlands.
The Chesapeake Bay is the largest and most productive estuary in the U.S. Unfortunately the health of the Bay and its tributary streams is threatened due to excessive pollutants. Outlined below are a few ways this project will improve water quality.
1) Reducing Pollution: The EPA established a regulation known as the Chesapeake Bay Total Maximum Daily Load (TMDL). This regulation, sometimes called a “pollution diet”, sets limits on the amount of nitrogen, phosphorous, and sediment that is allowed into the Bay. This project is planned to remove approximately 31 pounds of Phosphorus, 145 pounds of Nitrogen, and 3 tons of sediment per year.
Brookfield Park wet pond has been designed to help Fairfax County meet this regulation by releasing small amounts of stormwater to protect the downstream channel. The addition of sediment forebays at the intake points helps to efficiently treat, or clean, the stormwater before it gets to the main waterbody of the pond. These measures in turn allow the pollutants to settle to the bottom of the pond and therefore removing them from the water that flows out of the pond into Accotink Creek.
2) Restoring Habitats: The restoration of wildlife habitats is an important part of a healthy Bay ecosystem. Brookfield Park wet pond contains two kinds of marsh areas as well as floating treatment wetlands that will help remove pollutants from stormwater and create wildlife habitats for species such as ducks, insects, song birds, turtles, and fish that will thrive in these constructed habitats.
3) Protecting Watersheds: The health of many tributary’s that feed into the Bay depends on land use practices in the watersheds around them. Fairfax County is protecting the Accotink Creek Watershed by implementing several practices. Conservation areas have been established in the park to help protect the forested area around the pond. A feature has been designed at the pond’s outfall to dissipate energy from the spillway discharge and protect the downstream channel from erosion. Environmental friendly materials were utilized in the construction of the parking lot and part of the pond access road to encourage infiltration and improve water quality.
To determine where the final of this multi cache is found, explore the site around the pond and gather the information outlined below. Final is at N38 AB.CDE, W 077 FG.HIJ
A - the number of floating wetlands you can see from the observation area.
B - The informational sign at GZ lists how many specific features of this pond (listed A-??).
C - The number of tons of sediment this structure is estimated to remove from downstream per year.
D - Total number of letters of feature 5, minus 1.
E - Last digit of the pounds per year of Nitrogen that this structure is estimated to remove.
F - 1st digit of the facility ID - found on the brown sign just to the NE of GZ
G - Last digit of the pounds per year of Phosphorous that this structure is estimated to remove.
H - The number of letters in the 1st word of the first feature on the informational sign
I - Look at the name of the feature that rhymes with "neat!" To visit it, project a waypoint of 315 degrees (NNW) and 175 feet. Walk to that feature, and count the number of openings going across the first row (where this feature meets the pavement). What is the last digit of the # of openings?
J - How many letters are in the name of the watershed (omit the word creek)
Congrats to Aronel for being First to Find!
