Alberta’s new wet areas mapping initiative: a cost-effective approach to facilitate stewardship

Barry White, Alberta Sustainable Resource Development, Edmonton, Alberta Jae Ogilvie, Paul A. Arp, Forest Watershed Research Center, Faculty of Forestry and Environmental Management University of New Brunswick, Fredericton, New Brunswick

The panel on the left presents an overview of the GIS-based digital flow-channel, wet-areas and cartographic depth-to-water (DTW) mappingprocess for the currently available LiDAR coverage of Alberta. The result(WAM, or wet-areas map) involves the delineation of all pertinent flowchannels, all associated wet areas, and corresponding depth-to-waterunderneath the soil surface adjacent to all digitally recognized surface-water features. At the foundation of this process is the digital elevationmodel (DEM) and the digitized locations of all open-water features of thearea, i.e. streams, rivers, lakes, etc.The principle (center): the scale-dependent WAM process isimplemented through an ARC Macro Language (AML) script in ESRI’sARC/INFO Workstation platform and calls on additional functionalitythrough small C++ routines. The accuracy of the output products of thecartographic WAM process depends on the quality of the input DEMand/or river & stream data. The process has been tested and successfullyvalidated in the field through in-field GPS tracking on datasets ranging inresolution from SRTM (Shuttle Radar Topography Mission) DEMS at ~90mresolution to LiDAR-derived DEMs at sub-meter resolution. For province-wide DEMs, map features referring to flow channels, wetland bordersand road-stream crossings are generally within 40 m, 8 times of 10. WithLiDAR DEMs, this improves to within 4 m, 9 times out of 10.The process: the flow chart on the left illustrates how the flow-channel,wet-areas and cartographic wet-areas mapping process works and ismade to conform to already mapped open-water features such as lakes(or ponds) and streams. In turn, the process reveals further details aboutmany additional and otherwise as yet unmapped streams and ponds, aswell as the adjacent DTW conditions across the landscape.The product (bottom left): areas so mapped generally conform toalready mapped flow-channels and wetland borders as apparent from airphotos or other surface images. Combined with the DEM-derived flow-channels, the map also displays the topographic connectivity amongadjacent wetlands as well as many previously unmapped wet-areafeatures from small to medium-sized potholes. The same process is alsoused to contour areas that are dry and subject to frequent droughts,such as steep slopes and ridge tops.Special extension tools assist wet-areas map users to project and chooseamong alternative routes between any two control points along a newroad or trail segment. These alternatives arise from considering localbelow- and above-ground trafficability conditions, vehicle type andloads, and constraints re. operator safety and environmental protection,e.g., minimizing flow-channel crossings, rutting, and soil erosion andcompaction.Map applications: thus far, wet-areas map are used to facilitate “surprise-free” forest operations planning in major and very economical ways, e.g.:road access and trail layout, delineation of summer and winter harvestblocks, in-block harvest trails, wood landing sites, placement oftemporary and permanent flow-channel crossings; tree planting layout;on-board off-road navigation to avoid flow-channel and wet area traffic,summer through winter.

Alberta’s forested landscapes and parks are facing unprecedentedchallenges, such as …

… moving personnel and equipment towards fire- and beetle-affected areasacross wild terrain in a cost-effective and surprise -free manner

… minimizing the “footprint” of access roads and recreational trails acrossAlberta's forests, parks, rangeland, and wilderness areas

… re-configuring and rehabilitating existing road and trail networks

… inventorying hydrological features across the land, and identifying andlocating hydrological threats in a systematic, high-resolution manner

… regulators and partners on the landscape must have the best tools toensure sustainability.

… Alberta is a national leader in promoting and supporting innovativeresearch for sustainable land-use management and operations.

Within the newly formulated Integrated Land Management Framework for Alberta, the flow-channel, wet-areas and cartographic wet-areas map (WAM)

is essential for …

… Sustainable Resource Management,

to (e.g.) formulate natural resource policies, and to oversee and assist with natural resource management plans at technical

and managerial levels

… the Environment,

to (e.g.) visualize and assess source-sink impacts of developments (industrial, residential, recreational) on land and

water resources, according to topographically definable flow-channel,

wet-areas and drainage patterns

… Transportation,

re. (e.g.) facilitating, planning, maintaining and improving linear

transport structures, such as roads (paved, gravel, ice), power lines, pipelines and placement, and access to communication

towers

…Tourism, Parks and Recreation,

re. (e.g.) planning public access routes, and controlling the

growing dispersal of recreational activities, motorized as well as non-motorized; WAM will also assist trail planning and design

… Municipal Affairs,

re. (e.g.) urban and sub-urban planning and developments, in special reference to drainage

layout, and building and maintaining high-quality green

space and corridors

… the Energy sector,

to (e.g.) synchronize planning and access to oil and gas patches

with other land users, and in relation to soil trafficability

constraints; WAM is also important to oil sands

development, land re-mediation and impact assessments

… Agriculture and Rural Development,

to (e.g.) minimize impacts of multiple land-disposition access on surface

resources referring to farms, forests, rangeland, wildlife habitat and water

resources

LiDAR-derived flow-channel (blue) and wet areas with cartographic depth-to-water map (white to pink to red: 0 to 1 m DTW) @ 1 meter resolution, in the Ecosystem Management Emulating Natural Disturbance (EMEND) Project study area in the Clear Hills Upland, approximately 90km north-west of Peace River (denoted by red star on upper map). Map features overlain on hill-shaded orthophoto drape.

Sustainability of Alberta’s hydrological resources, including sensitive aquatichabitats, is under significant risk due to unprecedented land use challenges.Innovative planning solutions that are economic, timely and ensure positiveoutcomes are urgently needed by Alberta and our industry partners. Alberta hasbeen working closely with researchers at the University of New Brunswick since2004 to test the effectiveness of a cartographic depth-to-water mapping tool. Mapspredict the location of small water bodies such as ephemerals and wet areas whichare currently not known to resource planners but yet are sensitive to disturbance.This modeling approach has been adopted by governments and industry in easternCanada and in Maine where it has been particularly helpful in enhancing thesustainability and stewardship of forested landscapes, and in reducing operationalcosts. Successful research trials in Alberta’s foothills and boreal regions have movedthis approach from the research phase to full implementation. Efforts are underwayto map approximately 15 million hectares of forested lands in the foothill and borealregion of Alberta (panel to the right). Alberta’s mapping process will incorporatenewly acquired LiDAR data to produce maps of superior quality. Initial mappingproducts will be available in 2009 from Alberta’s Department of SustainableResource Development. These maps will significantly enhance the stewardship ofAlberta’s landscapes.

The Alberta Government is supporting the development of innovative GIS-based technologies for utilizing recently and currently acquired LiDAR-derived digital elevation

data for 15 million hectares, at meter to sub-meter accuracy and resolution.

Obtain thelocal DEM

Trench or “burn” these features into the

DEM surface

The DEM-based flow accumulation calculations

are then forced towards the trenches

Fill the trenches, and show new

flow channels in red

Display thecartographic

depth-to-water index (DTW, white

0 m, to pink, to dark red 1 m) next

To all mapped flows and shorelines

Cartographic Depth-to-

Water index

360

370

380

350

340 320330

390400

0420

310

400

0380

310

330

360

380

310

470

390

430

450

400

310

370

320

310

330

340

370

350

400

360

430

310

0

370

410

360

460

360

370

380

350

340

320330

390400

0420

310

400

0380

310

330

360

380

310

470

390

430

450

400

310

370

320

310

330

340

370

350

400

360

430

310

0

370

410

360

460

Overlay already mapped hydrographic

features on the DEM

Using WAM for on-board

off-road navigations

… Science community,

re: (e.g.) enriching and enhancing the understanding of ecosystem processes and those that affect biodiversity and productivity in

research trials already established as well as proposed; maximizing return

on previous investments and building new knowledge.

3D interpretation of predicted wet areas map (purple), over a varied land-use terrain (residential, agricultural, forest, streams and wetlands).

37