Black Branch 2

Small headwater stream in an agricultural setting with bedrock substrate. Flow is present but very low. Channel appears natural with minimal visible impairment. The agricultural adjacency on the left bank may contribute to nutrient and sediment loading during storm events.

The channel appears natural with no evidence of straightening, riprap, or other structural alterations. The bedrock substrate provides natural grade control. The channel dimensions appear appropriate for the drainage area. Minor score reduction because the agricultural adjacency may have historically influenced channel form, but the channel itself shows no clear alteration.

The channel is on bedrock which limits incision. Banks are low (under 3 feet) and the floodplain appears accessible on both sides. The agricultural land use in the watershed likely increases peak flows and flashiness. Some minor incision may be present but bedrock controls prevent significant downcutting.

Bedrock-dominated channel shows minimal sediment deposition — the hard substrate resists accumulation. Some fine sediment visible in low spots between rock surfaces. Overall deposition is minor, likely less than 10% of the bed affected. The bedrock naturally prevents significant sediment storage.

At current low flow, the stream is entirely shallow. Fast-shallow conditions exist where water flows over bedrock ledges, and slow-shallow conditions exist in small depressions. No deep water visible anywhere. The bedrock substrate and low flow conditions limit the variety of velocity/depth regimes.

Water is present but very shallow, barely covering much of the bedrock substrate. Approximately 50-75% of the channel has at least a film of water, but significant areas of exposed rock are visible. The flow appears to be baseflow during a dry period.

The bedrock substrate creates natural irregularities that function as riffles where water flows over ledges and drops. However, at low flow, many of these features are barely wetted. The riffle features are present but not optimally functioning at current water levels.

This is a bedrock-controlled headwater stream in the Nashville Basin of Middle Tennessee. The Ordovician limestone bedrock controls both channel gradient and planform. The stream is classified as a B-type based on moderate entrenchment, riffle-dominated morphology, and moderate gradient. The bedrock substrate prevents significant channel migration or incision. The channel is narrow relative to the valley, with floodplain access on both sides. The agricultural land use has likely not significantly altered the channel geometry due to bedrock control.

Left bank (right side when facing downstream) is low and moderately stable. Bank is partially protected by tree roots from mature sycamores and other deciduous species. No active erosion observed. The bedrock at the base provides natural stability. The agricultural field beyond the narrow buffer could contribute to bank instability during high flows, but currently the bank appears stable.

During winter dormancy, coverage assessment is challenging. Tree trunks and root systems provide some protection. Dense shrubs (some possibly invasive) provide additional coverage. Ground cover is sparse due to season. Estimated 60-70% effective coverage considering both dormant woody vegetation structure and remaining green ground cover. Some potential invasive species present.

Left bank has narrow riparian buffer transitioning to open agricultural field. The buffer width appears to be approximately 25-50 feet of woody vegetation before reaching cropland/pasture. A red barn/outbuilding is visible in the distance.

Right bank (left side when facing downstream) is moderate height (3-6 feet) with a large mature sycamore tree providing significant root stabilization. The bank is naturally vegetated with trees and shrubs. No active erosion observed. The bank appears to rise somewhat higher than the left bank, providing a slightly steeper profile.

The right bank has better vegetative protection with a wider riparian zone extending into woodland/scrub. Dense dormant shrubs and mature trees provide 70-90% structural coverage. The vegetation appears predominantly native. The right bank riparian zone appears wider and more robust than the left.

Right bank has wider riparian buffer extending into woodland. Large mature sycamore tree provides significant root protection and bank stabilization. Some open agricultural fields visible through vegetation on this side as well but at greater distance.

The left riparian buffer appears to be approximately 25-50 feet wide before transitioning to open agricultural land. For a channel approximately 3-5 feet wide, this represents roughly 5-10x the channel width, which would normally score higher. However, the buffer quality is compromised by apparent invasive species presence and the abrupt transition to agriculture. The effective buffer width considering vegetation density and quality is moderate.

The right riparian buffer appears wider than the left, extending approximately 50-100 feet into a mix of woodland and shrubland before reaching open agricultural land. This provides more robust filtering and habitat functions.

The riparian zone has a mix of mature trees, shrubs, and herbaceous vegetation, but the buffer is narrow on the left side and transitions abruptly to agricultural land. The winter dormancy makes the vegetation appear sparse. During growing season, this would likely score higher. Overall, the riparian vegetation is fair but not robust.

Currently in winter with bare deciduous canopy, shade is minimal (<25%). During growing season, the canopy of sycamores and other deciduous trees would provide approximately 50-75% shade. Score reflects the annual average considering seasonal variation. The canopy is present but not dense enough for full coverage even in summer due to gaps where agricultural fields are close.

The left bank buffer could benefit from widening through agricultural setback or planting additional native trees and shrubs. The right bank buffer is more adequate. Both buffers would benefit from invasive species management to improve native vegetation dominance and ecological function.

The bedrock-dominated channel offers limited epifaunal substrate. While bedrock surfaces can support some colonization, the flat limestone provides less habitat complexity than mixed cobble/boulder substrates. Some undercut banks and root wads from streamside trees provide additional habitat, but overall favorable substrate is estimated at 20-40%. The lack of large woody debris in the channel reduces colonization potential.

The bedrock substrate is naturally resistant to embeddedness. Some fine sediment is visible in crevices and low spots between rock surfaces, but overall the rock surfaces are clean and exposed. Embeddedness in the traditional sense is not a major issue on bedrock streams. Score reflects the natural condition of a bedrock-dominated channel.

No pools are visible in this section of the stream. The bedrock substrate creates a uniform shallow flow with no significant pool development. The entire streambed is visible. At higher flows, some depressions in the bedrock may form shallow pools, but at current low flow conditions, pools are essentially absent.

Fish cover is limited. The primary cover types available are overhanging vegetation (bare branches in winter, but would provide cover when leafed out), some undercut banks, and root mats from streamside trees. Deep pools, large woody debris, boulders, and macrophyte beds are absent. The shallow bedrock channel provides minimal refuge for fish.

No barriers to fish movement are visible within this section. The bedrock may create small ledges that could impede movement at very low flows, but no permanent barriers are evident. Score slightly reduced because the very shallow water depth at current flow could limit fish movement seasonally.

Very little large woody debris is visible in the channel. The narrow channel width limits the ability to retain large wood. Some small branches and twigs are visible but no significant LWD that would create habitat features. The mature sycamore trees adjacent to the channel should eventually contribute LWD, but currently the channel is largely devoid of woody debris.

Invertebrate habitat is limited by the bedrock-dominated substrate. Available habitat types include: some coarse gravel in crevices, minor undercut banks, and leaf packs accumulated in low areas. The flat bedrock provides minimal interstitial spaces for macroinvertebrate colonization. The absence of large woody debris, cobble/boulder substrates, and submerged logs limits habitat diversity. Score of 4 reflects the 3 habitat types present but their limited extent.

Score based on habitat assessment rather than direct observation. The clean bedrock substrate with flowing water and some crevice habitat suggests this stream could support at least facultative organisms (Group II). The agricultural adjacency may limit sensitive taxa. Winter survey timing reduces observability.

No macroinvertebrates were directly observed from the imagery, which is expected given winter conditions, low water, and the limitations of visual assessment from 360-degree photography. The habitat could support Group II organisms given the clean bedrock substrate and flowing water. Score assigned based on habitat potential rather than direct observation.

Suitable Habitat: No

The stream is too small and shallow to support significant aquatic species of concern. The bedrock substrate and agricultural setting are not particularly conducive to rare or threatened species. The mature sycamore tree with a visible cavity could provide habitat for cavity-nesting birds or small mammals.

No wildlife directly observed. The mature sycamore tree visible in the right bank view has a cavity that could serve as a den or nesting site. Winter survey timing limits wildlife observations. The rural agricultural setting provides general habitat for common species.

Water is mostly clear with a slight brownish tint likely from natural tannins and dissolved organics. At the shallow depths present, the bedrock substrate is easily visible through the water. No algal mats, sheens, or other water quality concerns are apparent. The slight turbidity may be from the survey crew's foot disturbance of fine sediments. Under ambient conditions, the water appears relatively clear.

No evidence of nutrient enrichment. No algal growth visible on the bedrock surfaces. No macrophytes present in the channel. The water is clear without green coloration. The adjacent agricultural land could be a potential nutrient source, but no visible impacts are evident at this location. The winter season may mask nutrient issues that could emerge in warmer months.

No direct evidence of manure or waste in the stream or on the banks. The adjacent agricultural land includes what appears to be cropland/pasture with a red barn visible, suggesting some agricultural activity. However, no livestock are visible and no fencing issues or direct access points are apparent. The riparian buffer appears to separate the stream from agricultural activities.

Currently in winter with minimal shade from bare deciduous canopy. During growing season, the sycamore and other deciduous trees would provide moderate shade (estimated 50-75%). The narrow buffer on the left side allows more solar exposure than ideal. The bedrock substrate retains some thermal mass. No thermal refugia identified. This is a warmwater stream based on location, size, and habitat characteristics. The agricultural adjacency contributes to solar exposure through limited buffer width.

No apparent permit violations or compliance concerns observed at this location.

Terrestrial Invasives Assessment

Aquatic Invasives Assessment

Low confidence in invasive species identification due to winter dormancy of most species. Some green-leafed shrubs and vines visible in the understory are tentatively identified as possible bush honeysuckle (Lonicera maackii) or privet (Ligustrum spp.) based on their retaining green foliage in winter, which is characteristic of these species. Japanese honeysuckle vine may also be present based on semi-evergreen growth habit. A growing season survey is recommended for more accurate invasive species assessment.