We are looking at putting in a "top dam" which would gravity feed most of the 14 acre property we are working on. One idea is to cut a driveway off the road, to provide access for the earthmovers and also to divert rainwater runoff into the dam. (Our neighbours downhill of us should love this as they all pay for the costly maintenaince of the road which gets washed out regularly)... The existing road runs along the spine of the ridge, and is cut into the landscape so that it has six feet vertical walls on either side... so, to get water off the road and into the dam, we would have to cut a similar depth trench into our land, at least at the top of the property. The height of the walls of this miniature gorge would have to start at about 6ft and would taper off gradually as the slope descends to the point where the land is at the same level as the road or lower; this would be the site of our main excavation. Does this sound too invasive? Is there a better way? The ridge itself would provide some catchment area, though probably not enough to fill the dam in drier times when we are using a lot of water. We could look into pumping water up there using various methods, and forget about the road runoff. But it seems a waste to just let it run down the road. Never having engaged in such earth moving activity before I would be grateful for any ideas and perspectives.