Interview with Dr. Al Karlin, Senior GIS Scientist, Southwest Florida Water Management District

24Jan2013

In this interview Dr. Al Karlin, Senior GIS Scientist, Southwest Florida Water Management District (SWFWMD) discussed the use of LIDAR and LP360 in managing the district's water supply. The SWFWMD is one of five water management districts in Florida; we serve ~ 5,000,000 people in our 10,000 sq. mile service area. Our four-part mission is to ensure an adequate and safe water supply, provide flood protection and protect natural water systems.

Could you give us an overview of the Southwest Florida Water Management District (SWFWMD)
and your role in the organization?

The SWFWMD is one of five water management districts in Florida; we serve ~ 5,000,000 people in our
10,000 sq. mile service area. Our four-part mission is to ensure an adequate and safe water supply,
provide flood protection and protect natural water systems.

I work in the “Watershed Management Program (Flood protection)” section of the District. We construct
Hydrological and Hydraulic (H&H) models to assist in Floodplain mapping (FEMA), Environmental
Resource Permit approval, and Watershed water quality and environmental protection.

How does LIDAR fit into your analysis process?

We think of the Watershed Management Program as a cyclical workflow that begins and ends with
topographic information. We start with surface topography to determine natural water flow paths, augment the surface flow with man-made systems (storm water pipes, etc.) and then construct a model. However, with building permits and other land alterations such as putting pipes into the ground to re-route water, surface changes occur. This requires new topographic data and updated models to be constructed. LIDAR is now the preferred means to obtain topographic data. We are also finding new uses for LIDAR such as roof drip line extraction to estimate non-connected impervious area, that were not available with “traditional” topographic surveys.

We have also found other uses for LIDAR including, (1) assisting the Regulatory engineers in determining
potential issues, (2) assisting Enforcement Officers in finding unauthorized activities, and (3) aiding
ecologists in identifying land patterns, historical/archaeological sites, and natural fire breaks. LIDAR data
serves as the source for our downstream modeling analysis. These software tools require gridded data
and the fact that LP360 rapidly exports ERSI Grids was our primary reason for purchasing it. LP360 is
also used by our Regulatory engineers for visualization to determine what would happen if something was built in a particular area with respect to water flow. It is also useful for interpreting hillshaded DEMs. The ecologists use it, for example, to detect historical mounds created by native Floridians without having to go into the field.

Read the full interview...