Census information for Amherst (Buffalo County, State of Nebraska). Contains: population counts from the 2010 Census and estimated counts up to 2016, Population Rings and much more.
Please try again later. This is the end point of a 70ft french drain constructed with 6in Multi-Flow product encased in coarse sand. The water is flowing into a 4inch PVC pipe via a tee connection. There is already some flow in the 4inch PVC from the upstream downspout lines that run under the french drain line. 1  Film & Animation.
1 Trench lines should be plotted out before you begin digging French drains. 2  You need to create your own mini-slope to carry the water down to its destination. 3  A grade of 1% (i.e., a drop of 1 foot for every 100 feet in length) is often recommended for French drains; others advise a drop of 6 for every 100'.