MULTI-SCALE WATERSHED MANAGEMENT: USING A CONCEPTUAL FRAMEWORK FOR

INTEGRATING MULTI-SCALE DATA

MULTI-SCALE WATERSHED CONSERVATION

HIERARCHY THEORY

Many Federal and State agencies, and programs such as the President’s Clean Water Action Plan are promoting a watershed approach to conservation.

Land managers are being encouraged to adopt a watershed or ecoregion approach to provide more holistic methods to natural resources inventory, monitoring, and management.

Traditionally studies in the biological sciences tend to be short term, and detailed when focused, or generalized when broad. Longer-term studies, while desirable, are often limited by funds, staff, and other priorities.

Hierarchy theory has provided a theoretical basis for dealing with the problems of scale, and a process for moving up and down scales to address specific issues ; . It suggests focusing investigations on a particular level of interest, where the level above becomes the boundary constraint, or context, used to explain the significance of the focus level, and the level below may explain mechanisms or processes controlling the phenomena at the focus level.

Although scientifically important, when strictly applied, this approach requires that each level have a direct hierarchical relationship with the next level above and below. Complex criteria must be met when ordering the mechanisms and processes, function or structure from one level to the next.

The traditional quantifiable hierarchy approach has proven valuable, however, there are times in conservation practice, when this is not always practical or necessary.

In conservation practice, choosing to look at just three levels at any one time, provides a more realistic concept. When looking at a natural resource phenomenon, such as a riparian area, we need to consider “where it occurs” and “what occurs in it,” or we may not see the whole picture – we can perhaps miss seeing the forest, while focusing on individual trees. The reverse can also be true, where we may miss the importance of the individual trees if we are thinking only of the forest as a whole, and missing entirely the soil, water and other factors that help the trees and forest grow.

Today there is a trend toward more multi-scale, holistic approaches , which can provide a vital complement to the more traditional studies carried out in the biological sciences on more narrow scales of space, time, and complexity

Watersheds are a natural choice for multi-scale work because, when defined by hydrologic features, they can be identified at different scales from large basins to small hydrologic units.

Collecting GPS data on the location of an alien plant species of special concern for eventual removal and long term monitoring.

The rainforest watershed we are working to protect is home to many endemic bird

species found only on MauiRemote sensing aids in locating stands of alien species growing in the rainforest of the East Maui Watershed.

Cells and tissue

Organisms

Populations

Communities

Organs and limbs

Robyn L. Myers, Ph.D., USDA Natural Resources Conservation Service Affiliate Scientist, NRCS Watershed Science Institute

State Landscape Ecologist, Watershed Planning Services, Davis, CA

Traditional Hierarchy Levels of Origination

THE TRI-SCALE CONVERGENT HIERARCHY

TABLE 2 – Example of TriSCH Applied to Watershed Management andassessmentTriSCHScale

Spatial Area Quantity Example Data types GeographicResolution

ContextArea(Macroscale)

Level N+1

Watershedcontext

One – large areadefined basedon local needs

Planning level ofagencies:Cosumnes RiverWatershed or EastMaui Watershed

Remote SensingCounty wide data(USGS DLGs, DRGs, )Planning Documents

40,470 hectaresor more

1:100,000 -1:250,000 maps

FocusArea(s)

(Mesoscale)

Level N

Focus Area orIssues(i.e. differentRiparian StreamCorridors, orissue such asNoxious Weeds)

Several -different focusstudy areas, onthe same ordifferent issues

Might be a riparianarea , river reach orother definable sectionof a larger watershed:Dillard Bridge area orKeanae Valley

GIS – with local Areaor Issue extent,including results ofdata integrated fromfield samples, andderived from quadmaps or DOQs.

1 - 40 hectares –or whatevermakes sense

1:24,000 maps

Site SpecificAreas

(Microscale)

Level N-1

Local sitestudies, datacollection(i.e. plots ortransects)

Many -localizedstudies withsite samplingmay occur

Small study areas,plots, or transects:plots and transectsaround Dillard Bridgeor in Keanae Valley

Site data(study data andmeasurements)Plots, TransectsGPS

1 acre or lessPoint specificdata, GPS points

(<1-30 meters)

Watershed and Riparian Corridor Examples:

The Tri-Scale Convergent Hierarchy (Figure 1.2) approach provides a conceptual framework for applying these ideas to watershed management and assessment, where the details below and the context above converge toward and influence, the primary level of focus. It differs from past approaches in that the three scales are defined conceptually, with landscape features that “make sense” rather than identifying features that can be quantitatively aggregated to the next level. Another difference, is that when choosing the conceptual features, the focus area should be chosen first. The upper level should then be chosen based on the management context in which the focus area occurs. The lower levels should be chosen based on what fine detail information is needed to better understand the focus level. In this way, the upper and lower levels are converging on the middle level to help bring a better understanding of the data and information collected on the focus area resources.

In the conceptual framework, the level of focus is considered to be the meso-scale, with the level above it the macro-scale, and the level below the micro-scale. For the purposes of watershed management and assessment, these scales will be referred to as “Context Area,” “Focus Area(s),” and “Field Site Areas.” In the TriSCH approach the actual scale of study areas for these levels, as well as the data resolution used to study them, are determined by the focus level. For example, the riparian area, or river corridor, is chosen as the focus area under consideration. The context area, then, is the watershed in which it occurs, and remote sensing imagery will be used to map it. Several field site areas may be chosen within the riparian focus area, to collect data on soils, plants, animals and so on, using the appropriate site sampling methods for each, and GPS to locate each sampling location.

However, the TriSCH approach benefits from the higher technology data and techniques as they provide three general scales of data collection, lending themselves well to tri-scale approach. For example, remote sensing and 1:100,000 or 1:250,000 maps (generally of county areas) provide a good base map of the greater watershed area. They provide a visual and physical context of the natural and human resources in the area. These data are good at the Context Area level. Aerial photography, DOQs (digital orthoquadrangles), 1:24000 (7 ½ minute quadrangle maps) and GIS data layers for specific resources provide a good scale of data for the Focus Area level.

However, when beginning a project and surveying existing GIS datasets, it is generally at the focus level where there is the least data available. It is at this scale that Focus Area projects need to, well, focus. This is where interdisciplinary teams, collecting data at field sites, can plan to collect data in such a way, that it will provide a good sampling for the focus level riparian corridor. By planning the field site data collection with the focus area, and context area in mind, it is much more likely that a complete picture will emerge of the higher levels.

Applying the TriSCH model does not necessarily require high tech approaches such as GIS, GPS, or remote sensing. It can be applied with traditional data recording, graphing, and mapping techniques. However, GIS is a natural way to integrate multi-scale data. The TriSCH model simply provides a way of thinking about the geographic areas of interest, and a way of organizing data collected at multiple scales.

Context Area

Focus Area(s)

Field Site Areas

Macro-scale – Level N+1“The Watershed” (Data: State or Ecoregion maps, Remote Sensing)

Meso-scale – Level N“Riparian Stream Corridor”(Data:Digital orthoquads, quads, county maps)

Micro-scale – Level N-1“Vegetation Plots”(Data: GPS locations of vegetation plots)

The TRISCH Approach Examples of the Conceptual Framework

The Context Area is the Windward East Maui Watershed, Hawaii

Focus was on the Ke`anae Valley area and Pi`inau Stream

Ground survey mapping, vegetation plots and transects, and GPS data were collected at specific sites.

Tri-Scale Convergent Hierarchy Approach

Contact the Author:

Robyn L. Myers, Ph.D., USDA Natural Resources Conservation Service

Affiliate Scientist, NRCS Watershed Science Institute

State Landscape Ecologist, Watershed Planning Services

430 G Street, #4164, Davis, CA 95616 (530) 792-5669 FAX: (530) 792-5794

robyn.myers@ca.usda.gov http://www.ca.nrcs.usda.gov/wps

The East Maui Watershed, Hawaii

Cosumnes River Watershed, Northern California

CONTEXT: The Cosumnes River Watershed extends from its headwaters in the Sierra Nevada mountains to the San Francisco Bay Delta. The NRCS is coordinating with other agencies and organizations, such as Cosumnes River Task Force and UC Davis.

THERE ARE TWO FOCUS AREAS:

The NRCS is conducting a Resources Inventory in the upper watershed, to be used by the Task Force as part of their overall effort to address flooding problems in the lower watershed.

The Army Corps of Engineers is studying the lower watershed working with agencies such as the Nature Conservancy and the University of California.

SITE SPECIFIC AREAS STUDY: One study involves researching the source of sediment around the Dillard Bridge, involving a time series of aerial photos to study the sand bars above and below the bridge. This photo sequence led geologists on the team to suggest that the bridge may be a victim of natural changes in the river, rather than the bridge being the cause of the sandbars. Further study, with many more time steps in the chronosequence, is underway.

This project was initiated by the East Maui Watershed Partnership. They were developing a watershed management plan (Context Level) and were looking for specific information on plant and animal species of special concern, both endemic and alien. A baseline GIS dataset was created for the 40,470 hectare watershed, that integrated remote sensing, aerial photography, and GPS referenced transect and plot studies (Site Specific Areas).

The Focus Area, Ke`anae Valley in this case, included a study of alien species invading the area, and comparison of the effectiveness of different scales of remote sensing imagery to detect them. The study also coordinated the aerial data collected with ongoing inventory and monitoring of native and alien species by The Nature Conservancy and other groups. A time series of six historic aerial photos were sequenced to show the spread of alien species over time.

1937 1957 1964 1987 1993 All years

The Cosumnes River Watershed is a large watershed in Northern California, draining a large part of the Sacramento basin. It extends from San Francisco bay, through the Bay-Delta and the foothills, and up into the Sierra Nevada mountains. A number of groups have formed along the Cosumnes River, some addressing flooding issues, others conducting research and restoration projects. The Cosumnes River Task Force is bringing all these efforts together.

More information on these studies may be found at:

http://www.ca.nrcs.usda.gov/wps