Colorado State University

IREM - The Integrated River Basin Environmental Management

System combines GIS, land use, habitat suitability indexes, economic models, and an optimization model to develop wildlife habitat management plans for river basins.


IREM is a tool to assist resource managers with effective data analysis, modeling, and decision support required for effective basin-wide planning, management, and optimization. This system can be used to identify management goals for the restoration and development of wildlife habitat in a river basin.

IREM was jointly developed by the U.S. Bureau of Reclamation and the Integrated Decision Support Group (IDS) at Colorado State University.

Geographic Information Systems (GIS) data has been has used to develop a Decision Support System (DSS) for the Lonetree Wildlife Management Area (Lonetree). Lonetree is a 32,890 acre tract of land located in central North Dakota, which extends down the Sheyenne River Valley. Lonetree was originally purchased with the purpose of building a regulatory reservoir as part of the Garrison Diversion Unit Project. Congress has since authorized making Lonetree a wildlife management area.

The Lonetree Wildlife Management Area

Figure 1: The Lonetree Wildlife Management Area

The principle objective of the DSS is to maximize wildlife habitat suitability by strategically locating habitat types required by selected wildlife species. The use of computerized methods for analyzing spatial information makes it possible to consider the spatial distribution of habitat requirements. Since field surveys and projections can be difficult and expensive, modeling wildlife habitat with a DSS can be a potentially lower-cost source of data.

Although Lonetree has been used as the prototype area, IREM can be used in other wildlife management areas as data becomes available. Therefore, IREM has two main objectives: 1.) to conduct a field demonstration of the analytical tools and techniques through the formulation of a habitat development plan for the Lonetree Wildlife Management Area in North Dakota, and 2.) to develop tools and techniques for more effective data analysis, data reduction, modeling, and decision support related to managing environmental resources.

The Software

IREM is an interactive wildlife management program using geographical information as the database. IREM evaluates habitat suitability based on spatial characteristics. The system uses the Geographic Resources Analysis Support System (GRASS) for the manipulation of spatial data. IREM is being written to run on either a Sun or Data General UNIX workstation. The user interface was developed using the "C" programming language combined with "OSF/Motif" and "Xt Intrinsic Libraries" for graphics.

Data Input

A vegetation type database for Lonetree in vector format (ARC/Info) was transformed into raster format (GRASS) to form a base map for the area. Lonetree is a large and diverse area that includes cropland being converted to wildlife habitat, wooded areas, and some tracts of native prairie.


IREM was developed to link a Geographic Information System (GIS) with a set of habitat models in a framework that allows the user to:

  • Evaluate the habitat suitability of different land areas for different species of wildlife.
  • Simulate management activities that modify landscape features.
  • Obtain results from simulated activities in terms of changes in habitat suitability and the associated management costs.

This interactive tool affords resource managers the ability to develop "what if" scenarios, and to graphically display changes in habitat suitability resulting from simulated landscape alterations.

Useful Tools

The DSS Framework provides three very useful tools for the wildlife manager to make decisions on how to modify the habitat of a management area to support a wildlife species:

  • The ability to calculate the habitat value for a particular area. This value is determined by established biological models based on the cover types available in the area.
  • A "what if editor" that allows the user to modify cover types, develop scenarios, and estimate costs associated with the changes.
  • A proposed optimization tool which is a non-linear numerical model that optimizes cover types to meet management goals with habitat or cost goals imposed on the solution.

Models are used to describe the habitat resources required by a particular species of wildlife. The models used in this system are based on the concept of a Habitat Suitability Index (HSI). An HSI is a unitless value between 0 and 1 that estimates habitat conditions based on characteristics of cover types, "1" representing optimum conditions. Since the relationship between cover types and the suitability of habitat can be described mathematically with an HSI value, habitat models can be a means of quantifying the effect of various habitat management strategies.

At the present time IREM contains five species: Gadwall, Sharp-Tailed Grouse, Gray Partridge, Pheasant and White-tail Deer. The addition of models for non- game species as well as other game species is planned.

To be effective, models must (1) define the resources to be supplied by habitat, (2) identify the landscape features that supply these resources, and (3) document the response of the animal to the supplied resources. This approach works well for simple relationships with landscape features which are uniformly distributed. However, resources are often concentrated in particular areas or clumped and optimum habitat consists of the juxtaposition of landscape features containing high habitat value. Habitat models coupled with a GIS can provide a powerful tool for modeling habitat management for large areas of diverse land-use types.

Evaluate Habitat Changes

"What if" scenarios allow you to evaluate the consequence of modifying cover types. Map areas can be selected by a square of variable size or by sections. Per acre conversion costs are inputted by the user to compute a rough estimate of the management action in dollars.

A cover-type map can be selected, and used for modeling the spatial location and extent of each cover type. Once a map is displayed any portion of the map can be selected and displayed in more detail. After the species has been selected, the user can compute the HSI. For each of the three requirements, a screen is displayed showing how the model computes the results. Management activities can be simulated to increase the habitat value of an area. Using the "What If" option, the user can "create" native grassland with a high habitat value in areas, such as cropland, that has limited nesting habitat value. The user can control the cover type amount and location, and estimate a cost for the changes.

IREM Decision Support Framework

Figure 2: IREM Decision Support Framework

Evaluate and Develop Scenarios

Once changes are made, the user can evaluate the altered landscape and determine changes in each respective HSIs. Other scenarios can be developed, and results compared with costs and respective changes in habitat suitability.