Lifespan of a Lake and Keeping On Top of Silt
Reading time: 10 minutes
Inside Silt Management
Silt is not an uncommon occurrence in lakes and ponds on golf courses, an effect of these spaces being surrounded by nature, but what it can cause is havoc on the oxygen levels in the water, impacting the water body’s wellbeing, its lifespan and the wildlife within.
Removing silt, and even better preventing it all together can fix a whole host of problems, from bad smells to unsightly algae, ensuring your lake is a focal highlight for your grounds or golf course, and a hospitable habitat for any fish and animals that may reside there.
Here Simon Powell, Otterbine’s business development manager, considers the impact of silt and how to keep on top of it.
What is silt?
Silt in its description is a contradiction in terms - a solid granular material or solid dust-like sediment. Geologically it’s classified by its grain size and texture through a sieve, and is assigned a letter according to whether it is gravel, sand, clay or organic.
It can be created with the erosion of rock as grains are transported through flowing water such as rivers, grinding down until they become silt sized. At such a point, this sediment can find itself washed into lakes and ponds through an inlet or watercourse where it can settle and become the layer of black silt you might be familiar with.
Alternatively, silt can come from organic matter washed in from surrounding fields or plants. Lakes and ponds that are tree-lined are particularly vulnerable to heavy siltation as dead plant leaves and other organic material fall from surrounding fauna into the water and build up on the lake bed.
Why is silt a problem?
As silt builds up on the bottom of lakes, it inevitably decays. Natural processes work to break down this organic matter using up oxygen levels from the water and this increases the demand on dissolved oxygen levels.
Without a sufficient level of oxygen in the water, anaerobic bacteria work to break down organic build up within the water and bottom of the lake. During this process, the bacteria will produce waste gas, which is what we can then smell.
Another issue with silt if left is that it reduces the depth of the water body and causes risk of flooding, similarly if there is an outlet that is also blocked with silt, heavy rains will cause flooding on the adjacent land, which is particularly disastrous if there is property on that land, if it is agricultural, or if it’s in use for leisure or commercial activity, for example a golf course or public park.