Patent ID: 7596999
Filing Date: 2009-10-06
Classification: G01F

Abstract:
1. Apparatus installed beneath the surface of soil for receiving a mixture of stormwater and entrained solids and for retaining and for monitoring the amount of solids which is retained as sediment, which comprises: a storm water-receiving chamber, buried within a porous medium beneath the surface of soil, shaped for receiving storm water in combination with entrained solids, and configured for allowing the stormwater to flow from the chamber while leaving behind a quantity of said solids in the form of sediment; a float, positioned within the chamber, having a combination of shape and weight which causes the float to be movable upwardly in response to rise in the level of water within the chamber; the float movable downwardly for resting on the surface of sediment at the bottom of the chamber when water above the sediment surface is absent from the chamber; a rod, interconnected with the float, extending upwardly though the top of the chamber; and, a vertically extending tube, attached to the top of the chamber, for containing and guiding vertical motion of the rod; wherein the float has a volume sufficient to displace water having weight equal to or greater than the downward force which results from the weight of the float and rod, so that the float and rod move upwardly when water within the chamber rises; and wherein the bottom surface area of the float is sufficient to support the float on the surface of sediment within the chamber without substantially sinking into the sediment, against the downward force which results from the weight of the rod and float, when water above the sediment surface is absent from the chamber.