Original article published in ESRI ArcNews Magazine in Winter 2012.
Edits my apply due to formatting.
GPS, GIS, and Lasers: Field Crews Assess the State of Northwestern Watersheds
Human activity such as logging and road building inevitably transform our environment, but federal agencies are collaborating to evaluate, protect, and restore some of the most vital and sensitive areas. Riparian zones – from the Latin word “ripa” meaning river bank – refer to rivers, streams, and surrounding land. They serve as habitats for diverse flora and fauna and have far-reaching influence on soil and groundwater conditions. When outside influences turn a lush, shaded, slow-moving stream into a barren bedrock chute, for example, the entire watershed can be impacted and invasive species can take over.
The Northwest Forest Plan helps ensure that scenarios like that are avoided – and even reversed. The plan’s policies and guidelines empower federal agencies to work together toward more sustainable management of federally owned lands that span from Northern California to the Canadian border, and from the Cascade Mountains west to the Pacific Ocean. In the crucial area of watershed conservation, their efforts are informed by comprehensive reports prepared by the Aquatic and Riparian Effectiveness Monitoring Program (AREMP). Each summer, adventurous AREMP field crews employed by the US Forest Service (USFS) and US Bureau of Land Management (BLM) set out to sample 28 watersheds, resulting in 250 watersheds sampled on a 9-year rotation. To determine monitoring site locations, the AREMP GIS team first identified watersheds with at least 25 percent of their stream channels lying within federal land. Of these watersheds, 250 were selected for stream sampling using a process that ensured a random, uniform distribution of watersheds throughout the Northwest Forest Plan area. Within each selected watershed, a similar process was used to select a random, uniform sample of stream survey sites. Because many other agencies and organizations also use this method to select study sites, AREMP findings contribute to richer overall knowledge about the sample areas and can help inform other environmental efforts. AREMP stream crews measure a variety of attributes including the shapes and sizes of streams and rivers, the location and position of large woody debris in the stream channel, and biological factors such as the types of aquatic insects and amphibians that are present. The result is an overall stream score for each watershed that reveals its health and enables comparisons with previous conditions.
“Integrating the laser with everything else creates streamlined workflows. Sometimes we’ll be measuring channel widths that are a meter or meter and a half wide with a depth of 10 to 15 centimeters, so highly accurate laser offsets are important to us.”
— Mark Isley, AREMP Data Manager
The AREMP team’s findings help inform a variety of National Forest Plan efforts. Near Roseburg, Oregon, for example, before riparian zones were protected, logging activity resulted in decreased amounts of woody debris, altering the streams and making them less hospitable to the salmon which once thrived there. Federal and state governments and local non-profit organizations placed trees and boulders in riparian zones to help build up substrate levels to create better fish habitats. Upon returning to the sites like the ones in Roseburg, field crews found that the restoration work did in fact result in increased stream condition scores.
The AREMP team also helps look for the presence of invasive species. When they come across aquatic invasive species during their stream surveys, the appropriate government organizations are informed so they can take immediate action before the problem worsens. After visiting four to ten sites within a watershed, the crew moves on to the next watershed. To get to remote sites in places like Olympic National Park in Washington, which has some of the highest watershed scores due to limited human activity, crews must hike 10 or more miles. In some cases, horses are used to help transport survey gear to especially rugged sites. Crews work from May through September, with some special monitoring projects extending into October.
A key piece of the field data collection that lays the groundwork for the surveys involves measuring river or stream morphology. This creates a map of the channel based on the width, depth, and path of the water and how it changes over time. To take accurate measurements, two crew members work together using a laser with an electronic compass and prism setup from Laser Technology, Inc. called the MapStar® Impulse System, which is waterproof and can be mounted for extra stability on rough terrain. Measurements are immediately displayed on a backlit LCD display to ensure accurate readings in shady environments like riparian zones. A built-in serial port brings the compass and laser data directly into surveying software running on Esri’s ArcPad® platform on rugged hand-held devices. Customized data input forms specific to AREMP’s work automatically appear when a laser measurement is taken, and the devices also record the location via a GPS sensor. These measurements are used to create a map using a toolbar extension for ArcPad® called LaserGIS®, providing context for each study site. Other crew members measure shade levels; sample for amphibians, invasive species, and small invertebrates like insects, snails, worms, and crayfish; and collect additional data. Those data are inputted through custom ArcPad applets and forms, and are automatically related to the site map.
Along with the data collected in the field, the GIS team brings in additional datasets, including vegetation from remotely sensed imagery and GIS road layers from the BLM and Forest Service. These data enable them to analyze key riparian factors across full watersheds, such as miles of road within riparian areas and the frequency of roads crossing streams. All of this information together results in a comprehensive picture of the health of Northwestern watersheds. The AREMP team’s hard work has not gone unnoticed. They’ve received a Riparian Challenge Award from the Western Division of the American Fisheries Society and a National Interagency Service First Award for their collaborative, multi-agency monitoring program that supports the success of the Northwest Forest Plan.