The main jetty at Port Burwell was built about a hundred years ago. During those years, sand has accumulated to the west of the jetty creating a large beach and some additional dunes at the Port Burwell Provincial Park. At a presentation to Norfolk County Council, Peter Zuzek asserted that there are 10-million cubic meters of sand trapped at Port Burwell. At other times he has stated there are 15-million cubic meters of sand trapped there. So I wondered, how much sand has accumulated there and made my own estimate. I came up with somewhere between 1-million and 2-million m³. Is my rough estimate more accurate? I cannot say, but I trust mine more as I know what assumptions were made.
I acknowledge that the definition here of trapped sand is nebulous. For my estimate I did not include the land created where the current Port Burwell sewage treatment plant is located. I am assuming there would be no intention of letting that wash away.
Here is my calculation method. The length of the ‘new’ beach is about 2.5 km or 2,500 meters. At the widest, beside the jetty, the new beach is about 100 meters wide. At the other end it has tapered to zero, so the average with is 50 meters. The depth of the new sand is more difficult to estimate. I used a guess of 5 meters.
2500m x 50m x 5m = 625,000m³. To include the additional offshore (under water) sand for a total estimate of 1.25-million m³, or about a tenth of Peter Zuzek’s estimate.
Then I wondered how that volume of sand compares to the amount we have lost from just our Bayham property in 19 years. Our non-eroded land is at least 25 meters above lake level. The cliff edge has receded about 40 meters. The length of the property along the lake over 1,300 meters.
1300m x 40m x 25m = 1.3 million m³. That is a conservative estimate of the volume of sand with some clay that we have lost to the lake. That does not include the sand and clay displaced by the gulley that crossed our property in 2014 and continues to grow north, just east of Godby Road, to this day. The shoreline properties to the east of ours have similarly high cliffs and erosion rates. The higher the cliff, the faster the erosion due to hydrostatic pressure. More about that elsewhere.
someofabeach.ca 