Dam and Hydropower Influences
One water control structure, Dawt Mill Dam, is located on the mainstem of the North Fork River in Missouri. The dam is a low dam (less than 10 feet high) and is located 1.8 miles above Tecumseh. The original Dawt Mill Dam was constructed in late 1800s in order to supply power to the machinery of Dawt Mill (Cochran 1980 and Robins 1991d). Both the dam and mill were replaced shortly after the turn of the century. The dam was rebuilt again in the 1970s after flood debris severly damaged the dam (Cochran 1980). Other water control structures within the watershed in Missouri include Noblett Lake Dam (Noblett Creek), Rockbridge Dam (Spring Creek), and Althea Spring Dam (Althea Spring Branch). All were constructed prior to 1940. Figure Hc01 displays the location of the previously mentioned water control structures.
The North Fork River flows into Norfork Lake which has a recognized beginning at the confluence of Bryant Creek. Norfork Lake Dam was completed in 1944 and is located 4.8 river miles upstream from the confluence of the North Fork with the White River near Norfork, Arkansas (USACOE 1993). Norfork Lake Dam impounds 1,983,000 acre feet of water with a surface area of 30,700 acres at top of flood control pool.
There have been no significant channel alterations anywhere throughout the North Fork Watershed. Small channelization projects have probably occurred on private property and also from road and bridge construction. However, these activities currently are not considered to be a major threat to the river system. Currently (1999) there are no planned state transportation projects involving bridge construction within the watershed from 1999-2004(MDT 1999).
In 1998 there were 24 permitted gravel removal operations within the watershed (Figure Wq06) (USACOE 1998). The negative impacts of gravel mining have been shown to include channel deepening, sedimentation of downstream habitats, accelerated bank erosion, the formation of a wider and shallower channel, the lowering of the floodplain water table, and channel shift (Roell 1999).
Between 1987 and 1991 the Missouri Department of Conservation inventoried counties within the North Fork Watershed for unique natural features (Smith 1990; Ryan and Smith 1991). The inventories recognized seven categories of natural features: examples of undisturbed natural communities, habitat of rare or endangered species, habitat of relict species, outstanding geological formations, areas for nature studies, other unique features, and special aquatic areas having good water quality, flora, and fauna. These studies identified 177 potential natural features in the North Fork Watershed. Of the 177 sites, 124 had exceptional or highly significant natural features. The North Fork River and Bryant Creek were recognized as highly significant natural features. Roaring Spring, Hodgson Mill Spring, Althea Spring, Crystal Spring, Rockbridge (Morris) Spring, and Double Spring were recognized as highly significant spring sites.
Since the initial natural features inventory effort the Missouri Natural Heritage Database (NHD) has been created. The database lists many of the features which are included in the Missouri Natural Features Inventory. The database, which is updated frequently, is a dynamic representation of the occurrence of many natural features in Missouri. Currently the database contains 294 features for the North Fork Watershed. These include 49 examples of 18 types of natural communities: The North Fork River, Bryant Creek, and Spring Creek are recognized as significant examples of Ozark creek and small river communities (MDC 1999c). Unique and outstanding dolomite bluffs, glades, and dry mesic chert forests are common throughout the watershed. Recorded occurrences of natural features currently (1999) in the NHD for the North Fork Watershed include
- Creeks and Small Rivers (Ozark)-3
- Dolomite Glade-10
- Dry Chert Forest-1
- Dry Limestone/Dolomite Cliff-1
- Dry-Mesic Bottomland Forest-1
- Dry-Mesic Chert Forest-3
- Dry-Mesic Chert Prairie-1
- Dry-Mesic Sandstone Forest-1
- Fresh Water Marsh-1
- Headwater Stream (Ozark)-1
- Mesic Limestone/Dolomite Forest-1
- Moist Limestone/Dolomite Cliff-3
- Moist Sandstone Cliff-3
- Pond Shrub Swamp-2
- Prairie Fen-2
- Shrub Swamp-1
A detailed description of these terrestrial natural communities can be found in The Terrestrial Natural Communities of Missouri by Nelson (1987), while a detailed description of Missouri's aquatic communities can be found in Aquatic Community Classification System for Missouri by Pflieger (1989)
Undoubtably more examples of natural features exist within the watershed. However due to many circumstances including the limited access to private land and the large land area, many features may be as yet unrecorded. Therefore, the previous listing of features should not be regarded as final. However, this listing does provide a good cross section of the types of communities which can be found within the watershed.
There are currently (1998) 3 DSP-3 projects within the North Fork Watershed. These are intensive rotational grazing programs sponsored by the Natural Resource Conservation Service (NRCS) and involve alternative watering systems. All are in progress. There are 3 completed Landowner Cooperative Projects including a cedar tree revetment project completed in cooperation with the United States Forest Service and located at the North Fork Recreation Area. One other project is currently awaiting landowner approval (Pratt personal communication 1998). Table Hc01 lists all stream related projects in the watershed.
Stream Habitat Assessment
In 1996 and 1998, stream and riparian habitat quality were evaluated at 13 sites within the North Fork Watershed. Of the 13 sites, 6 were located in the Bryant Creek Subwatershed, 6 in the North Fork Watershed above the Bryant Creek confluence, and 1 in the Norfork Lake and Tributaries Subwatershed. These sites generally corresponded to 1996 fish community sample sites. Habitat quality was assessed using the MDC Stream Habitat Annotation Device (SHAD II). Selected SHAD data was entered into a geographic information system (GIS) database based on a numerical system which enabled more efficient analysis of data. Sites were evaluated based on the following SHAD categories: "streambank erosion", "streambank erosion protection", "percent timbered stream corridor", and "narrowest width of timbered corridor". Numerical values associated with different levels of condition for each category were then assigned to left and right streambanks and corridors evaluated with 1 being extremely poor and 5 being excellent. These values were then averaged to give an overall grade for the site (Figure Hc02). The lowest grade within the North Fork Watershed was a 3 (fair). Three sites received this rating. Five sites were rated as 5 (excellent). The remaining five sites were rated as good.
There appears to be no significant distribution pattern of SHAD sites relative to grade. This illustrates the complications of using SHAD data as a means for determining watershed and even subwatershed habitat condition. Depending on site selection methodology as well as the level of homogeny of habitat within a watershed, the SHAD can be a very site specific method of habitat evaluation. Thus, in most cases, the more broadly that SHAD data is applied to a watershed, the less accurate it becomes.
Perhaps one of the more difficult attributes of a watershed to attempt to quantify is stream habitat. This is due to the fact that there are several dynamic characteristics which make up stream habitat. To evaluate all of these characteristics individually and accurately for an entire watershed is a monumental task and beyond the scope of this document. Thus, the next best thing is to evaluate a characteristic that has the most impact on all aspects of stream habitat. This is, arguably, riparian corridor land cover/land use. Riparian corridor land cover effects many aspects of stream habitat. These include, but are not limited to water temperature, turbidity, nutrient loading, sand/gravel deposition, instream cover, flow, channel width, and channel stability. These in turn have effects on still other characteristics of stream habitat such as food availability, dissolved oxygen, cover, spawning areas, etc.
Evaluation of riparian corridor land cover/land use within the North Fork Watershed was accomplished using Missouri Resource Assessment Partnership Phase 1 Land Cover Data. A buffer zone 3 pixels (90 meters) wide was created which corresponded to a 1:100,000 hydrography coverage for the watershed. This was split into segments no longer than 0.25 miles long (Caldwell, personal communication). Percent land use for each segment was then calculated. Land cover/land use categories included forest, woodland, grassland, cropland, urban, and water. Percentages of these categories were then calculated for riparian corridors within each of the 30 fourteen digit hydrologic units, the 6 eleven digit hydrologic units within the watershed, as well as the whole watershed.
Results for the entire watershed indicate that riparian corridor land use consists of more forest/woodland (64.9%) than grassland/cropland (34.2%). Combined percentages for the remaining categories are less than 1% of the total riparian corridor land cover/land use in the watershed. Of the 6 eleven digit hydrologic units (HUs) within the watershed, the Upper North Fork HU has the highest combined percentage of forest/woodland corridor land cover/land use at 71.2%. It also has the lowest combined percentage of grassland/cropland corridor land use at 28.3%. This is due in large part to the fact that much of this section is part of the Mark Twain National Forest. Table Hc02 gives riparian corridor land cover/land use percentages for all fourteen digit hydrologic units within the watershed as well as percentages for the three major drainage sections of the watershed and the total watershed. Figure Hc03 presents a graphic representation of riparian corridor land cover/land use for all fourteen digit hydrologic units within the watershed.
An aerial stream survey of the North Fork River Watershed was made during March and April, 1996. The survey flight covered the entire length of the North Fork, Bryant Creek, and many other major tributaries. A catalog of the flight, highlighting stream and riparian destabilization areas and other significant landmarks has been completed. Highway and topographic maps have been labeled according to the video index time. The catalogs also include an index of slides taken during the flight. Information from this survey will be useful for a variety of projects such as future habitat assessment, assisting landowners with problems associated with stream bank erosion and deposition, reviewing gravel mining permits, selection of aquatic biota sampling sites, etc.
Cold Water Habitat
Approximately 39 miles of stream within the North Fork Watershed are designated for cold-water sport fishery (Figure Hc04)(MDNR 1996a). Approximately 14 miles of the North Fork River are designated for cold-water sport fishery. Table Hc03 lists additional stream segments designated for cold-water sport fishery.
In an effort to further quantify cold water resources within the North Fork Watershed, instantaneous stream temperatures were recorded at many stream crossings within the watershed during August of 1991, 1992, 1993, and 1994. Results from this preliminary study were then used to determine sites for placement of thermographs (long term temperature recorders). These were placed at 47 selected sites in the summer of 1995 and 1996 (Table Hc04). Thermographs were programmed to record temperatures every 2 hours. Period of record for the thermographs varied from 12-64 days. Average stream temperature at each site for period of record was determined and then compared to average air temperature (Mountain Grove) for period of record (Figure Hc04). Figure Hc05 displays results of comparisons of average stream temperature and average air temperature for sites exhibiting an average air temperature of 80 degrees Fahrenheit or higher. The higher average air temperature at these sites enables a more confident determination of spring influenced sites. Figure Hc06 shows the comparison of temperature graphs between air temperature, a spring influenced site, and a non-spring influenced site. The limited period of record for some thermograph sites as well as a relatively mild summer in 1996 limits the use of some of this data. Results of comparisons between sites with different periods of record are questionable. Furthermore, sites with shorter periods of record or periods which occur later in the summer typically exhibit cooler average air temperatures and thus a smaller gradient between the average air and average stream temperature. Additional temperature study will be required in order to further determine spring influence within the watershed.