Precision Conservation and LiDAR

by Gene V. Roe

Having been involved with GIS – Geographic Information Systems for the past 30 years I was recently pleasantly surprised to see a new term – “precision conservation” come across my computer screen. I remember when “Precision Agriculture” was developed in the early 1990’s, driven in large part by the availability of low cost GPS – the Global Positioning System. The basic concept was to micro- manage agricultural fields using a 10m by 10m grid system to variably apply fertilizer based on soil tests for each grid.

The technology was all the rage for a 5 year run, in fact one of the satellite companies launched a precision agriculture business, but it never quite lived up to the promise and hype. I believe the techniques have shown to be valuable, but generally for large scale agricultural operations. Precision agriculture was never able to produce the return on investment for small to medium size operations.

 

The enabling technology for precision conservation is LiDAR – Light Detection and Ranging. From the simplest of explanations LiDAR is similar to radar except that laser light is typically used instead of radio waves. The goal of precision conservation is to dedicate scarce resources—time, money, energy—to identify places where pollution and erosion are disproportionately severe and the potential for improving water quality and reducing soil loss are disproportionately great.

LiDAR comes into play because it is the most cost effective method for developing high accuracy digital elevation models or DEMs. Essentially these DEMs are the 3D version of the standard USGS topographic map, which of course was 2D with contours to indicate the difference in elevation. It was up to the viewer to “see in 3D” by knowing the rules about contours and their relation to the topography. With a DEM, software and a computer you can now actually see the terrain model on the screen and perform a number of land conservation simulations on the model.

LiDAR-derived DEMs can also be used to precisely identify the most sensitive areas for erosion and the extent of flooding for a given water elevation. These DEMS can also be used to identify the most likely areas for water pollution to develop. Armed with this detailed mapping information conservation agencies can make more informed decisions about where to apply scarce resources in order to get the “most bang for their buck”.

A conference on precision conservation is being held March 29, 2012 in St. Anthony, Minnesota. The Freshwater Society, the conference’s major sponsor, is a 44-year-old Minnesota nonprofit organization dedicated to educating and inspiring people to value, conserve and protect water resources. Dave White, chief of the U.S. Department of Agriculture’s Natural Resources Conservation Service and a strong proponent of targeting, will give the keynote address. David Mulla, a University of Minnesota scientist who has been a national leader in researching technologies to aid such targeting, will give an overview of new and emerging tools and strategies.

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