GeoCAS Citizen Science.

Erosion Mapping

Erosion mapping in the USVI


Welcome to erosion mapping in the Virgin Islands.

Erosion is the removal of soil and rock by wind and water.
Eroded material travels downhill towards the sea. As they travel, eroded rocks and soil change the flow of water over the land, cutting new stream channels, filling floodplains, creating deltas, and settling on nearshore marine communities.

Human activities have increased the rate of erosion many times over natural rates. Road construction exposes hillsides from which soils are eroded until slopes return to the angle of repose , where the amount of energy needed to carry more material down hill is greater than what water and wind can provide. Lawns do not protect soils from the energy of raindrops as well as trees. Dirt roads often become streams and the road bed gets carried away. Exposed bedrock fragments as it heats and cools every day, and falls down slope onto roads. Water that is forced to run in small channels carries away soil, leaving only rocks behind. Bare soil at construction sites is loosened by moving it around, and vulnerable to wind and water. Construction often includes directing overland flow away from buildings creating new stream channels.

Soils that get deposited downstream affect ecosystems. Wetlands and lowland stream beds are filled by sediments. Sediments smother benthic marine life, including seagrasses and corals, which are support and feed juvinile fish that grow into what we put on our tables.

We often see the product of poor land use management when it rains and the water turns brown or after it rains and sediments and rocks are left on the roads. Sometimes we see sediment plumes These events are symptoms of poor land use management uphill from where we see them.

This mapping project is for the documentation of land use practices that are likely to produce erosion and erosion events. Please take a picture of the event or practice and add a point to the map.

To add a point to the map:

  • Navigate the map so you can clearly see the place where you want to place a point on the left hand side of the map.
  • Click on the icon with a pencil at the top left of the map window. Choose any of the icons in the window that appears.
  • Click on the map at the location you want to add a point.
  • Choose answers to the questions in the popup window by clicking on one of the options for each question.
  • Click somewhere else on the map to save the information. Click back on the point to add an image if you have one.
  • If you want to see what was entered for other points in the map you can click on them in the map.
  • If you are having trouble with the size of your screen you can open the map application in a new window by clicking here .