What is an EarthCache?
According to Groundspeak and the Geological Society of America, an “EarthCache is a special geological location people can visit to learn about a unique feature of the Earth. Visitors to EarthCaches can see how our planet has been shaped by geological processes, how we manage its resources, and how scientists gather evidence.” To claim a find for this EarthCache, you will have to provide answers to questions by observing Duke Pond. See http://www.earthcache.org/ for more information.
Know before you go: Parking is tricky to find at Duke. It is recommended to park at 125 Science Drive (near Duke Chapel) and walk to this EarthCache. It is a bit of a walk over to the pond. The trails map on the Geocaching app highlights many paths around campus to walk on. **Parking may be few and far between to find on certain days**
Duke Pond:
Duke Pond was constructed in 2015 as a holding reservoir for water entering a cooling plant while reclaiming land to harbor a flourishing lacustrine ecosystem and promote sustainability. The reclaimed pond was built on top of a streambed with the goal of being a retention basin.
What is a retention basin?
Retention basins are areas that can collect stormwater runoff from heavy rains, which can ultimately protect against flooding events. Retention areas are beneficial for areas such as Durham County. About 43% of the county is considered to be urban or suburban; in these areas, impervious surfaces inhibit runoff from entering the soil. Roads and concrete effectively become a barrier against the soil surface and prevent water from infiltrating the ground. Impervious surfaces have also led to the stunting of vegetation growth in certain areas by blocking plant roots from being aerated.
In most retention ponds, runoff gets transported to a retention pond via artificial or natural stream systems. As for Duke Pond, two streams help bring in water. As water enters the pond, a forebay helps separate most sediment from the water column. Many retention ponds typically contain lots of vegetation on their shorelines. Vegetation, in the form of grasses, shrubs, and trees, helps stabilize the ponds, especially if they are human-constructed. Vegetation is crucial to slow down the process of shoreline erosion. Plant roots stabilize sediment in place and soak up water. Plants also help reduce the spread of pollutants and contaminants in the environment by absorbing them.
Logging Tasks:
- Observe the turbidity of the water. Does the water in the pond appear clear, cloudy, or opaque?
- Bodies of water with high turbidity contain suspended sediment particles. Based on your answer to question 1, do you think Duke Reclamation Pond effectively captures sediment and nutrient runoff?
- Are any visible characteristics of retention ponds that you observe at the GZ? Note specific examples.
- As of June 2019, earthcaches now contain required photo logging tasks. Please provide a photo of yourself, your GPSr, or a personal item that proves that you have visited this site. Please post this in your log.
Sources:
https://www.epa.gov/eg/industrial-wastewater-studies-miscellaneous
https://sustainability.duke.edu/campus-lab-under-construction/cal-endorsed-sites/reclamation-pond
http://nwrm.eu/measure/retention-ponds
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