General repository for spatial data and methods used to create bathymetric maps for the water bodies included in NETN's water quality monitoring protocol.

​Objective of these surveys was to collect depth data of sufficient density to derive a bathymetric map of the lakes and ponds undergoing monitoring by the Network. Basic methods involved superimposing a grid on the pond, navigating to each grid point, drill a hole in the ice and take a depth measurement. The balance of effort and suitable model resolution resulted in the use a varying grid sizes between the water bodies. Grid points were calculated in ArcGIS by applying the free Repeating Shapes tool (http://www.jennessent.com/arcgis/repeat_shapes.htm) to the target waterbody's shoreline polygon. A Trimble RTK (R8 base/rover receivers and a TSC3 Controller) was used to navigate to each of the grid points. A 4 1/2" ice auger connected to a portable drill was then used to make a hole in the ice and a weighted vinyl tape was used to measure the depth to the nearest cm. In some circumstances it was deemed necessary to record more depths: 1) near the edges of the pond where the grid was not an ideal fit and 2) around what was determined to be the deepest part of the pond. We used a combination of tabular and spatial data processing steps to convert depth sampling data to create a digital bathymetric map. Detailed procedures are attached as holdings.