
3 minute read
Farmland Ponds
Farmland Ponds
By MIKE O’CONNOR
Ecologist at IRD Duhallow
One of the best things you can do for nature is to create a pond. A wide range of species will utilise the ponds in some way or another including ducks, frogs, dragonflies, damselflies and bats. Through our two EIP projects here at IRD Duhallow (the Duhallow Farming for Blue Dot catchments Project and the Owentaraglin River Project), we classify farmland ponds as either ‘biodiversity ponds’ or ‘silt settlement ponds’. Biodiversity ponds provide a habitat for wildlife to live, breed and forage. These were once a common feature on farms in Ireland, where they were sometimes used as a water storage facility for cattle. These can be constructed by digging a hole, no deeper than 1.5m, in a field with a continuous supply of water. Water may be already present if the field is wet or can be diverted from a farm drain. A pond liner will not be required as long as the soil is claybased. While any pond will likely yield benefits for wildlife, ideally the pond should have a range of depths to allow a diversity of aquatic plants to grow. It is best practice to allow the pond to vegetate by itself. Although it will look like a hole in the ground at first, within a year an abundance of plant species will begin to colonise the pond. Settlement ponds are usually installed in existing drains or water is diverted from existing drains or farm roadways into the settlement ponds, with the aim of reducing the amount of sediment entering rivers and streams. This sediment can smother Freshwater Pearl Mussel or salmon eggs and can have pollutants attached that threaten water quality. A two or three chamber sediment pond is dug with an overflow channel after each chamber. Silt that enters the first chamber is deposited and clean or cleaner water overflows into the second. By the time water reaches the river, much of the sediment will have been deposited in the settlement pond. Of course, the first pond chamber will fill up over time and will have to be cleaned out every one to two years depending on the size of the pond and other environmental factors. The sediment cleaned out from the pond will be rich in phosphorous and can be carefully spread on the land, taking care not to leave the sediment in a heap. Before installing your farmland pond, always check to see if the proposed location is within a Special Area of Conservation. If this is the case, consent will be required from a relevant public authority before works commence.