In this paper, I show how we can construct the light intensity field at the pool floor using approximate operators. A light intensity field can provide information about the geometry of the water surface. Inversion using patterns obtained from ray tracing and binning suffers from a large null space- i.e. many surfaces can produce the same patterns at the bottom of the pool. Future directions include using the proposed geometric inversion approach in three dimensions, and formulating and implementing the inversion problem using a realistic light intensity field.