OVERVIEW

This second quarterly report discusses progress made during the period September 1 to December 31, 1998. Work continued to progress in task areas begun during the first quarter. In addition, the task of developing the overarching structure of the monitoring protocol and the rationale behind the protocol began during the quarter. Task areas discussed in this report are:

Protocol Development

GIS-Based Analyses

Field Data Collection

 Protocol Development

Monitoring has frequently been called ‘mindless monitoring’, a derogatory phase meant to imply that there is little or no rational or thought supporting the collection of a time-series set of environmental measurements. However, a well-designed and maintained environmental monitoring program can furnish the evidence of environmental change (Burt, 1994). To provide this evidence of change, the question arises: what should be monitored? Underwood (1996) suggests that environmental monitoring only be undertaken with a "clear advance understanding of the nature, time-courses, and likely effects" of the range of possible disturbances. Others (Eaton and McDonnell, 1998; Pickett, 1991) have recommended the construction of conceptual models of the systems being evaluated to guide selection of monitoring sites and measurable parameters. If a monitoring program is structured with anticipated processes and results in mind, then little monitoring (in the routine sense) may be necessary (Underwood, 1996). Instead, a limited amount of data collection may allow assessment both of the results and of the causes of a particular environmental change.

Watershed-Based Framework

With the above in mind, we began the development of a top-down, overarching structure for the monitoring protocol during the second quarter. A key aspect of the monitoring protocol is that it will utilize a watershed-based framework for data collection and analysis. Watershed-based frameworks are being recommended by many for ecosystem analysis (Frissell and others, 1986; Gregory and others, 1991; Allan and Johnson, 1997; Johnson and Gage, 1997). The adoption of a watershed-based framework for the protocol is founded upon the concept that water, sediment, solute, and energy fluxes link watershed headwater conditions to downstream water quality, stream, and riparian conditions.

Our approach for devising the monitoring protocol includes construction of a watershed conceptual model to guide the data collection strategies. Some of the interesting issues we will necessarily have to address in devising the protocol include various ‘confounding factors’ that complicate cause-effect relationships in the watershed. A few of these gleaned from our literature review are:

The processes of environmental change may be slow, subtle, complex, or rare (Pickett, 1991). For example, erosion processes are frequently very rapid, occur episodically, and occur at short time scales, whereas sedimentation processes are typically much slower and more easily detected at long time scales (Cluer, 1995). A data collection procedure devised to monitor one type of process may not be effective for monitoring other types.

History matters. Environmental changes are frequently contingent upon the previous history of change. Therefore, establishment of a watershed monitoring site may require some level of retrospective analysis to provide baseline data (Davis, 1989).

Complex Response. A singular perturbation in a watershed (fire, for example) may result in a tintinnabulation of several downstream erosion and sedimentation episodes due to linked feedbacks amongst erosional, transport, and depositional processes (Schumm, 1973; Humphrey and Heller, 1995). Because of this phenomenon, monitoring of present-day downstream processes may actually be reflecting upon past upland environmental changes.

Allogenic versus Autogenic Changes. Some changes are natural progressions within a system (autogenic) whereas others are the result of external forcing (allogenic) (Hickin, 1983). A river, for example, quite naturally changes its position by wandering about its valley and occasionally cutting off a meander. A monitoring protocol should be able to discern between autogenic and allogenic changes.

 These are a few of the issues we are tackling in developing the protocol. We have been and will continue our literature review, particularly with respect to climate change and anthropogenic effects upon watersheds, to guide protocol development.

GIS-Based Data Maintenance

In any long-term monitoring program, handling and maintaining the tremendous volume of data being collected can be overwhelming (Pickett, 1991). One component of the protocol that we began development during the second quarter was a system for data collection and management. Because many of the data being collected vary spatially, we are employing a geographic information system (GIS) for data maintenance. Additionally, many of the data selection and analysis methods are spatially based and therefore readily adapted to a GIS. To enable GIS usage, all data collection locations are being assigned a Universal Transverse Mercator (UTM) metric coordinate (northing and easting) to identify their positions on the earth’s surface.

The general data collection and storage procedure we have developed to date includes:

Developing watershed GIS coverages (or layers) for topography, geology, soils, vegetation, and imagery from available sources. GIS coverage development begun during the first quarter continued into the second quarter. GIS coverages have been completed for the two Little Bear River basin watersheds, and are in various stages of completion for the other watersheds.

Selecting data collection points using the above GIS coverages and random, systematic, and stratified sampling procedures or combinations thereof.

Having a field crew collect the data from the appropriate sample point and entering it onto a data collection form. Eventually, this part of the collection process could utilize a data logger. Field crews locate sample points using GIS printed air photo images displaying sample point locations and a table of sample point UTM coordinates and a global positional system (GPS) unit.

Data are entered from field sheets into simple computer spreadsheet templates, saved as data files capable of being read by the GIS.

The data sets are linked to the GIS as data set coverages.

 We are implementing the data storage part of the protocol using the ArcView GIS and a dBase data file format. As the project progresses, we expect to expand and refine this system to allow point and click data selection and various spatial and temporal data display capabilities.

GIS-Based Analyses

In addition to the basic GIS coverages described above, we are deriving several coverages that are being used to define flow pathways and wetness characteristics along these pathways. These pathways are the linkages between upland areas and downstream riparian and stream sites. Using digital elevation model (DEM) data, we create the following coverages: slope, flow direction, specific catchment area, and wetness. Each of these coverages is a grid, with a different parameter value recorded for each grid cell. For our analyses, we are using grid cells than are 100 m² (0.01 hectare) in area.

The ‘final’ outputs of this initial GIS analysis of the data are the specific catchment area and wetness index coverages. The specific catchment area ‘a’ is defined as upslope area per unit contour length (m²/m). Beven and Kirkby (1979) developed the concept of specific catchment area for use in hydrologic models that represent runoff generation by the saturation from below mechanism. Figure 1 illustrates the derivation of this concept. Within the GIS, are based upon the number of upstream contributing cells is calculated, and is then divided by the length of the side of a cell, 10 m in these analyses.

Field observations by many scientists indicate that higher soil moisture or areas of surface saturation tend to occur with increasing specific catchment area, decreasing slope, thin soils, and an increased rate of watershed recharge (precipitation input minus losses). To delineate flow pathways, we are employing a wetness index using these concepts that has been devised by Pack and others (1998):
 

W = min [ R a / T sin × ), 1]

where:

W = is the wetness index with an upper bound of 1 representing saturation,
R = steady-state recharge rate over the watershed (m/hr),
a = specific catchment area (m) derived from the specific catchment area coverage,
T = soil transmissivity (m²/hr) derived from the soils coverage, and
Sin × = land slope derived from the slope coverage.

Figure 2 illustrates the spatial variation of the wetness index within one of the study watersheds. By the end of the third quarter, we anticipate completing these GIS flow path analyses for the Utah watersheds.

Field Data Collection

Field data were collected in the two Little Bear River basin watersheds during the second quarter, and the initial data collection for those watersheds is approximately one-half complete. With the onset of winter conditions in early November, many Utah ski resorts opened in advanced of their typical Thanksgiving opening dates, and our field data collection season came to an abrupt halt. We anticipate field data collection will be on hold until about March or April. We are, however, using this intervening time to assess the data that have been collected and determine whether or not field data collection procedures should be modified.

The first phase of field data collection is allowing us to test and refine the protocol procedures, assessing how well they work and how much time is required for a field effort to collect data for an entire watershed. We provide herein a very brief synopsis of a few of these procedures, as we have conducted them to date.

Upland Data Collection

Field data collection has been grouped into two distinct efforts: upland site collection and flow path network collection. At upland sites, a variety of vegetation, soil, and hydrologic data are being collected. As we described in the first quarter report, a watershed’s uplands are comprised of a set of hillslopes that begin as interfluves at drainage divides and terminate at the riparian corridor. Each hillslope consists of one or more overland flow elements (OFE’s) of (relatively) spatially uniform soil, vegetation, geomorphic, topographic, and hydrologic properties. For the REMAP protocol, the OFE is the smallest spatial unit used for characterizing upland conditions. Within a watershed, three OFE’s of each type are sampled and within each OFE, parameters are sampled at five randomly selected points (Figure 3).

The OFE sample point is located on the ground using an aerial photograph and a GPS unit. At the point, a stake is driven into the ground, and a 30-meter (100-foot) tape is stretched perpendicular to the hillslope in an easterly direction. Data collection is undertaken at various distances along the tape, with some offsetting so as to acquire measurements with as little disturbance as possible. Four of the upland data collection procedures we have been using are described below.

Vegetation type and density. Vegetation cover types are collected using the "point intercept on a transect method." A total of 100 points along the tape are sampled using a 0.3-meter spacing along a metric tape. A thin rod is extended downward at each 0.3-meter (1-foot) marker along the tape until it hits vegetation, litter (fallen vegetation), rock (greater than 1.27 centimeter or ½ inch), a pebble (less than 1.27 cm or ½ inch), or bare soil. The first contact or "hit" is recorded and marked in the appropriate row of the cover data form. These data are aggregated to derive percentage cover type and density.

Percentage canopy cover. Percentage of cover at a height of 1.2 meters (4 feet) or taller is determined along the tape. Starting distance and ending distance where cover height equals or exceeds 1.2 meters (4 feet) is recorded onto a vegetation cover data form by plant variety. The data are summed and divided by 30 meters to obtain a percentage cover value, by plant variety.

Infiltration rate. Soil and hydrologic data are collected at the same OFE sites at which vegetation data are collected. However, these tests are undertaken at the 10-, 20-, and 30-meter-mark locations on the tape. The rate of water infiltration is measured using a 7.62 cm (3 inch) single ring infiltrometer cut from a piece of PVC pipe driven into the ground 5 cm. Rate of fall of water is measured by refilling the infiltrometer at recorded time intervals until a constant drop rate is obtained. Time-rate values are recorded and converted to infiltration rate values.

Soil Shear and Compressive Strength. Soil compressibility or unconfined strength is determined with a Soiltest pocket penatrometer. At each of the three measurement locations along the tape, three measurements of strength are made, for a total of nine measurements at each OFE site. Similarly, three measurements of shear strength are made using a pocket shear vane tester.

 Flow Path Data Collection

About a dozen sites along the flow path network in each watershed are being selected to depict the physical and ecological character of the steam channel and surrounding riparian zone. These sites are located 1) where sampled OFE flow paths enter the channel network, 2) by random placement along the network, 3) at the watershed outlet, and 4) at specific locations where environmental conditions are judged to be "representative" of some specific characteristic. Typically, a 30-meter length of valley is characterized at each site. However, if the channel is wider than 2 meters or the valley flat is wider than about 5 meters, a longer length of valley is measured. Eleven transects are made across the entire width of the valley floor and up onto the adjacent hillslopes. These transects are used to 1) establish riparian cover conditions, 2) survey valley floor topography, and 3) aid in the mapping of valley floor geomorphology. Much of the information collected at each reach site is basic data that must be transformed. Survey data, for example, are transformed into topographic maps (Figure 4). These same data are also being used in a backwater analysis program to determine stream power and shear stress under various flow conditions.

REFERENCES

Allan, J. D., and Johnson, L. B., 1997, Catchment-scale analysis of aquatic ecosystems: Freshwater Biology, v. 37, p. 107-111.

Beven, K., and Kirkby, M. J., 1979, A physically based, variable contributing area model of basin hydrology: Hydrological Science Bulletin, v. 24, p. 43-69.

Burt, T. P., 1994, Long-term study of the natural environment - perceptive science or mindless monitoring: Progress in Physical Geography, v. 18, p. 475-496.

Cluer, B. L., 1995, Cyclic fluvial processes and bias in environmental monitoring, Colorado River in Grand Canyon: Journal of Geology, v. 103, p. 411-421.

Davis, M. B., 1989, Retrospective studies, in Likens, G. E., ed., Long-term studies in ecology: New York, Springer-Verlag, p. 71-89.

Frissell, C. A., Liss, W. J., Warren, C. E., and Hurley, M. D., 1986, A hierarchical framework for stream habitat classification: viewing streams in a watershed context: Environmental Management, v. 10, p. 199-214.

Gregory, S. V., Swanson, F. J., McKee, W. A., and Cummins, K. W., 1991, An ecosystem perspective of riparian zones: BioScience, v. 41, p. 540-551.

Hickin, E. J., 1983, River channel changes: retrospect and prospect: Special Publication No. 6, International Association of Sedimentologists, Blackwell Science, Oxford, p. 61-83.

Humphrey, N. F., and Heller, P. L., 1995, Natural oscillations in coupled geomorphic systems; an alternative origin for cyclic sedimentation: Geology (Boulder), v. 23, p. 499-502.

Johnson, L. B., and Gage, S. H., 1997, Landscape approaches to the analysis of aquatic ecosystems: Freshwater Biology, v. 37, p. 113-132.

Pack, R. T., Tarboton, D. G., and Goodwin, C. N. 1998. The SINMAP approach to terrain stability mapping. 8th Congress of the International Association of Engineering Geology, Vancouver, British Columbia, Canada, 21-25 September 1998.

Pickett, S. T. A., 1991, Long-term studies: past experience and recommendations for the future, in

Risser, P. G., ed., Long-term ecological research - an international perspective: Chichester, John Wiley and Sons, p. 71-88.

Schumm, S. A., 1973, Geomorphic thresholds and complex response of drainage systems, in

Morisawa, M., ed., Fluvial geomorphology. Proceedings Volume of the Fourth Annual Binghamton Symposia Series: Binghamton, New York, State University of New York, p. 299-310.

Underwood, A. J., 1996, Spatial and temporal problems with monitoring, in Petts, G., and Carlow, P., eds., River Restoration: Oxford, Blackwell Science, p. 182-204. 

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