Getting the Dirt on Martindale Pond
On February 13, five volunteers descended on Martindale Pond in Shelly Creek to measure the depth of sediment that has collected in the pond over the years. Martindale Pond is where Coho Salmon smolts spend the winter to avoid the turbulent flows of the Englishman River during the winter rains. Each spring, we install a smolt trap that allows us to count them as they begin their migration back into the Englishman River. We have counted up to 8,000 in one spring, so Martindale Pond is an important site for the Englishman River Coho population.
Martindale Pond has been filling up with sediment which is the result of erosion of the creek banks. This results in there being less and less space in the pond for the smolts to occupy. MVIHES would like to have this excess sediment removed from the pond to make more room for the smolts, but first we need to determine how much sediment there is to remove.
We did this using wooden dowels with a scale in centimetres written on them. We placed one end of the dowel gently on the bottom of the pond and measured the water level using the scale on the dowel . Then we pushed the dowel down into the muck until we hit solid ground and measured the water level off the dowel again. The difference between the water level with the dowel pushed into the muck and that before it was pushed into the muck gives us the thickness of the sediment layer at the bottom of the pond. The average thickness of the sediment is 28 cm, however, as we got closer to where Shelly Creek enters the pond, the thickness increased to 70 and 90 cm (almost 1 m thick). The creek channel itself has 90 cm of sediment.
The next step is to put together a plan to have the sediment removed. Stay tuned for futher developments!