NETMAP VALLEY WIDTH MANUALS
NETMAP VALLEY WIDTH MANUAL
NETMAP VALLEY WIDTH VERIFICATION
NETMAP VALLEY WIDTH CODE

Either the fish-bearing portion of the network is defined during the initial terrain analysis or the user applies a NetMap tool to define fish-bearing streams. Once a watershed, subbasin, or stream segment of interest is located, loading pre-made maps of all base parameters in the tool kit allows ready access to visual information, such as erosion potential, valley morphology, confluence effects, and wood accumulation types (Table 1).

NetMap uses finer scale digital topographic data (LIDAR) when available. The hillslope scale of resolution is 10 2 m (based on 10-m DEM) and the channel network is divided into discreet segments of between 20 and 200 m. Analyses can be extended to larger scales ( Ͼ 10,000 km 2 ) if necessary.

NETMAP VALLEY WIDTH CODE

A rea- sonable scale of analysis, given the computing requirements of NetMap’s tool kit, is approximately 10,000 km 2 (240,000 acres), an area that is further subdivided into hydrologic unit code (HUC) subbasins of sixth to seventh fields ( ϳ 5,000 to 10,000 ha 12,000 to 24,000 acres), or into user-defined subbasin polygons. Within the tool kit, watersheds are located by visual identification on regional maps or by name. One goal of NetMap’s generic terrain database is wide- spread coverage across regions to support watershed science and resource management, including encouraging interdisciplinary and interorganizational communication and problem solving. Here we illustrate eight of them in context of resource management applications. NetMap contains approximately 25 tools for analysis of watershed attributes and their relationship to various aspects of resource management.

NETMAP VALLEY WIDTH MANUAL

This facilitates creation of calibration functions and manual override (manually correcting predicted values), thereby offering the potential for increasing the accuracy of digital terrain databases over time.

NETMAP VALLEY WIDTH VERIFICATION

A “field link” tool in NetMap streamlines field verification of digitally derived data.

Any user of computerized terrain databases should verify their results in the field when possible.

In contrast, predicting confluence effects in tributaries based primarily on relative differences in drainage area between tributaries and mainstems (e.g., Benda et al. For instance, the accuracy of channel gradients and widths of valleys is highly dependent on the resolution of digital data (e.g., 10 m versus 30 m DEMs), although accurate relative measures are achievable using 10-m DEMs (Clarke and Burnett 2003). Some terrain parameters are more sensitive to data resolution than others. The resolution of available digital data is an important constraint on the accuracy and use of terrain databases in natural resource management. Thus, channel segment predictions of gradients, valley widths, and confluence effects in NetMap can provide rea- sonable working hypotheses on the nature of finer scale habitat morphology. For example, based on sediment transport theory, steeper valleys are typically associated with faster flow and coarse substrate, in contrast to wide valley floors with lower gradients that are associated with lower velocity flow, smaller substrate, and sinuous channels. This is based in the well-recognized hierarchical scaling relationships between watershed landforms and smaller-scale habitat morphologies (e.g., Frissell et al. A major benefit and central tenant in using digital terrain databases in natural resource management is that large-scale terrain features can be related to smaller-scale habitat attributes and potentially to biological assemblages that might be found within a given set of physical conditions. Sev- eral applications of the tool kit are briefly outlined below using examples from a terrain database we have assembled in pursuit of regional coverage that currently extends to 110,000 km 2 (27 million acres) in the Pacific Northwest (Table 3).

NETMAP VALLEY WIDTH MANUALS

In addition to base parameters (Table 1) and the suite of tools (Table 2), the educational aspect of NetMap is enhanced through over 400 pages of hyperlinked technical manuals and reference materials. NetMap automated analyses cover habitat typing, channel classification, channel disturbance potential, sediment and wood supply, core habitat areas, habitat diversity, erosion potential, overlaps among roads, erosion risk, and sensitive habitats, and sort- ing and ranking of subbasin-aggregated attributes across large watersheds (Table 2). The tool kit simplifies display and analysis of terrain data sets for both the GIS specialist and neophyte alike. additional watershed parameters (approximately 30) that are relevant to many facets of natural resource management, and serves as an educational plat- form for interpreting watershed environments.

Netmap valley width