In order to determine which of the three excavation sites could have potentially contributed to the sedimentation of the three lakes, it is necessary to determine the watershed boundaries and the contributing drainage areas of the system of lakes. Catchment basins (watersheds) can be determined by connecting ridge lines and dividing lines. Ridge lines will follow the elevation isocontours and dividing lines are perpendicular to the elevation isocontours at the end and start at the confluences of streams. Using the map on the textbook website displaying the elevation data, determine the following:
a. How many confluences are displayed on the map?
b. Delineate the watersheds using the elevation isocontours. The total drainage area of the study area is approximately 238 acres.
c. Determine which of the three lakes may be affected by accelerated sedimentation.
d. Determine which of the three excavation sites may be responsible for the accelerated sedimentation of the lakes.