E. Conclusions and Recommendations
Since the beginning of the NRWS-WetScape project many of the goals and objectives for the system have evolved with changes in technology, availability of data, and the state of wetland ecosystem science. The WetScape 3.0 interface reflects this evolving technology. The current version of software is "beta-tested" and should go through an expanded testing phase with subsequent development before being released outside Reclamation. Also, knowledge of UNIX and GRASS are assumed for some of the interface features and there is specialized training required to implement this system for a study area.
This phase of development has produced a WetScape 3.0 interface with documentation on how to use it and training in related specialized technology for Reclamation. The objectives listed in section 4.0 have been achieved in this phase successfully. The specific progress for the five primary items is listed here:
- Testing of the WetScape 2.0 Interface and Refining the WetScape 3.0 interfaceWetScape 3.0 can handle large data sets and can create scenarios as well as manipulate the data of existing scenarios. The capabilities of the interface to model the flooding of off-channel wetlands and to evaluate the impacts of wetland storage in a watershed have been improved.The user can now manipulate categories of GIS maps in order to optimize their use. The cell editor can now be used to paint cells continuously on the screen. The colors of raster map categories can now be modified. A filter box can be used to view a subset of maps during selection. The Interface can evaluate multiple water source seeds at the same time. The interface for using project/scenario/workspaces has been re-designed and improved.
- Improve the Stability of the WetScape 2.0 interfaceUnder this task an extensive testing of different combination of actions was undertaken and some debugging of the combinations that create problems have been corrected for WetScape 3.0.
- Application of WetScape 3.0 to an Devils Lake area with Prairie PotholesA dataset was developed for the Devils Lake area and standard datasets were developed for terrain-based features. The storage volume capabilities have been tested on an application to Devil's Lake basin.
- Documentation for WetScape 3.0 and this phase of developmentAll the documentation listed has been developed and reviewed by Reclamation.
- Transfer Technology (train Reclamation personnel)The Reclamation
personnel have been trained how to import maps into GRASS so that
they can be used as part of WetScape 3.0 interface. Reclamation
personnel have been trained on how to use and modify the WetScape
The current phase of WetScape development assumes future development of the system. Though the technology and the science continue to evolve and therefore may reshape future development items listed below have been identified.
3.1 WetScape Analysis Modules
As discussed earlier in Chapter III: Results and Discussion, the primary functionality of WetScape is in the analysis modules. The Basin Wide Siting (BWS), Basin Wide Analysis (BWA), Projected Wetland Analysis (PWA) are in a beta-testing level of competition with the functionality defined and implemented.
- Basin Wide Siting (BWS) - This analysis module is generally designed to be utilized for the initial review of landform characteristics that influence selection of specific sites or areas of interest. The BWS module provides tools to assist users in defining criteria to apply spatial analysis to raster map information. This is accomplished through a model development interface called the Spatial Analysis Model Interface (SAMI). The SAMI is used to create script programs comprised of a sequence of GRASS operations that are applied to accomplish specific functions.
- Projected Wetland Analysis (PWA) - The PWA tool is designed to allow the user to evaluate a selected site area in greater detail. It is an important WetScape utility because it allows the user to evaluate the actual physical topography of an area with respect to projections of local surface flooding conditions. The user places an artificial control line, either open or closed, to define the area to be examined (Figure 1). A set of vertical elevations can then be selected to evaluate the water area and volume corresponding to flood stage. Three elevation zones can be specified to show the areal extent associated with each depth. These features might be employed to examine stage volume characteristics, or evaluate how a created wetland might respond to differing water surface elevations.
- Basin Wide Analysis (BWA) - The BWA analysis module consists of several models that develop totalizing reports for aggregating attributes assigned to the spatial data imported to the system or data generated by other analysis modules. For example, attributes associated with zone features defined in the PWA module could be compared for different hypothetical implementation strategies. In the most simple form, BWA supports totalizing spatial features according to area, volume, or linear attributes. BWA models can be designed to take advantage of the interactive environment of the WetScape interface to work with the other analysis tools, SAMI models or as preliminary stages for use of external resource models. Support for interface with other external hydrologic and water quality models would be undertaken in subsequent development stages.
- Water Demand Module - This module can estimate the consumptive use of an area from evapotranspiration of the vegetation. A per unit area consumptive use coefficient can be entered for each category of a vegetation map and estimated for local areas over time, based on weather data. Note, the dataset for any area using WetScape must be populated to use this module.
The additional four modules are in various stages of conceptual development. In some cases this may mean some broad ideas about the scope of the module have been defined, and in other cases such as CSA and CDB shell scripts have been developed to begin implementing the functionality. The basic functionality for the modules is as follows:
- Local Site Evaluation (LSE) - The purpose of the LSE module will be to provide interaction with detailed information for local wetland sites. Data exchange is anticipated through AutoCAD "DXF" file and ASCII Flat File for detailed design characteristics such as soil, vegetation, and/or elevation maps. This will include import and export features.
- Case Study Analysis (CSA) - The purpose of this module will be to import data from local existing or past wetland sites for the purpose of restoration or re-recreation.
- Case Data Base (CDB) - The purpose of this module will be to assemble a database of local existing wetland sites with data from sources such as the Wetland Inventory Survey and Bureau of Reclamation studies for reference by the CSA module.
- Water Quality Loading (WQL) - This module is envisioned to model the projected "foot-print" of constructed wetlands on basin-wide water quality.
- Hydrologic Loading (HYD) - This module is envisioned to model the projected seasonal and annual water demand of constructed wetlands from basin-wide sources.
The CSA and the CDB have some preliminary scripts that can be used interactively from a UNIX prompt. The WQL and HYD have the basic functionality defined, but have not begun in their implementation. With the development of the entire eight modules, the conceptual needs of terrain-based wetland siting should be addressed.
4.1 Devils Lake Prairie Pothole Region
Many important issues have generally been associated with the character, size, and number of potholes that have been drained in the general region draining to the Devils Lake area. During recent flooding years attenuation of runoff provided by through storage within the potholes appears to have been overcome by the runoff volume generated during a wetter hydrologic regime and flood levels in several lakes have risen and presented a threat to many improvements to the basin. As a result, the following two major question areas have arisen.
- What role do the prairie potholes play in this basin condition?
- What are the water quality issues associated with this change in land use?
A currently proposed research effort would explore the feasibility of conducting analysis to begin answering the first of these questions involving estimation of the total available surface storage and possible recovery of lost prairie pothole storage. More detailed questions might include discussion regarding the appropriateness of a data base that can be developed using off the shelf data digital data products vs. more elaborate data set development efforts. The following questions could be addressed by the terrain-based method:
- How much storage volume is present in the prairie pothole terrain available and how much can be identified with current elevation coverages?
- How will those areas where less precise coverages is available impact the analysis goals of the project (i.e. where the DEM and DLG map units are in meters and not feet)?
- What improvements could be achieved by performing more complete mapping (i.e. identify critical areas (i.e. identify critical areas to improve data and develop this data)?
To evaluate this approach the following questions should be addressed.
- What resolution of prairie pothole dimension can be extracted during analysis at the available horizontal and vertical mapping resolution.
- What impact will the resolving power play on the final basin wide estimation of volume?
- How much of the lost attenuation of surface runoff can be attributed to converted prairie potholes?
- What is the feasibly of recapturing a portion of this holding capacity?
- Which areas should be considered, and how much volume could be recovered?
- Can the approach and coupled field efforts characterize the current pothole drainage pattern and model a suitable recovery approach with reasonable success?