I want to build a small dam across a hillside stream on my land to create a header tank from which to extract water for my water supply. (NB I already have the right to extract - the house has taken its modest share of the water from this stream for a couple of hundred years - but I need to construct a new header tank further down the stream due to a boundary change.)
At one point the stream narrows and the banks tighten. At that point the stream itself is about a foot across and the stream and the banks around it form a shallow u-shaped bed about 5 feet across. If I built a wall of some kind across there as a dam, I could create a pool about 2 foot deep by 4 foot wide and 3 foot long. That's similar to the size of the existing header tank.
My tentative plan is to use the many sizeable stones lying around to make a kind of wide dry stone wall on either side of the stream itself, but cementing the stones together as I ago instead of leaving the wall without mortar. Obviously, building a cemented wall in running water would be tricky, so I plan to build the walls up on both sides to about 8 inches, then use a lintel to bridge the central channel where the water flows and continue to build on top of the lintel. The water would be left a gap in the centre of the wall.
Once the walls had cured I could fill up the central channel with stone, which would perhaps slow the water enough to form a pool from which I could extract the water using a filter and an MDPE pipe. (Incidentally I would create a kind of overflow for the water so that it made no significant change to the overall flow rate.)
Does this sound feasible? If so, do you have any tips? E.g. should I use blocks instead of stone, what kind of cement should I use to bind stones etc.
TIA
At one point the stream narrows and the banks tighten. At that point the stream itself is about a foot across and the stream and the banks around it form a shallow u-shaped bed about 5 feet across. If I built a wall of some kind across there as a dam, I could create a pool about 2 foot deep by 4 foot wide and 3 foot long. That's similar to the size of the existing header tank.
My tentative plan is to use the many sizeable stones lying around to make a kind of wide dry stone wall on either side of the stream itself, but cementing the stones together as I ago instead of leaving the wall without mortar. Obviously, building a cemented wall in running water would be tricky, so I plan to build the walls up on both sides to about 8 inches, then use a lintel to bridge the central channel where the water flows and continue to build on top of the lintel. The water would be left a gap in the centre of the wall.
Once the walls had cured I could fill up the central channel with stone, which would perhaps slow the water enough to form a pool from which I could extract the water using a filter and an MDPE pipe. (Incidentally I would create a kind of overflow for the water so that it made no significant change to the overall flow rate.)
Does this sound feasible? If so, do you have any tips? E.g. should I use blocks instead of stone, what kind of cement should I use to bind stones etc.
TIA
