Black Branch 2

Small headwater stream in agricultural setting. The bedrock substrate and low flow conditions suggest a stream that may experience intermittent low-flow stress. Agricultural land use on the left bank may contribute nutrient and sediment loading during runoff events. No visible signs of severe impairment at this location.

The channel appears natural with no evidence of straightening, riprap, or structural alteration. The bedrock substrate provides inherent grade control, limiting downcutting. Minor scour is evident but appears to be within natural range. The channel is slightly incised into the bedrock but this appears to be a natural feature of bedrock-controlled streams in this region.

The stream appears slightly incised into its floodplain, with banks approximately 3-6 feet above the current water level. However, the broad agricultural floodplain on the left side suggests the stream still has some connection to its floodplain during larger events. Agricultural land use and potential drainage improvements in the watershed may have altered the hydrologic regime, increasing flashiness and reducing baseflow.

Very little sediment deposition is visible. The bedrock substrate dominates and there are no significant point bars, mid-channel deposits, or pool filling. The bedrock-controlled channel naturally resists sediment accumulation, with loose fragments appearing to be locally derived from the bedrock rather than transported deposits.

At current low flow, the channel is dominated by shallow conditions. Most of the visible water appears to be shallow runs over bedrock (fast-shallow) with some slow-shallow areas where water pools slightly behind bedrock ledges. Deep pools are not evident, and the uniform bedrock substrate limits the development of diverse velocity-depth regimes at this flow level.

Water fills approximately 30-50% of the channel width at this low-flow stage. Significant areas of exposed bedrock substrate are visible in the channel, particularly along the margins. The water appears concentrated in the deepest portions of the bedrock channel.

Some riffle-like features are visible where water flows over bedrock ledges, but the flat bedrock substrate creates more uniform flow conditions than would be typical for a gravel/cobble-bedded stream. The natural bedrock steps create some variation, but riffle-pool sequences are not well developed at this flow level.

This stream is best classified as a Rosgen Type B channel with bedrock control. The limestone bedrock provides inherent grade stability and limits vertical and lateral adjustment. The moderate sinuosity and presence of a floodplain on at least one side suggest some meandering development despite bedrock control. The stream functions more as a bedrock-controlled run at current low-flow conditions. The Central Basin limestone geology of this area near Wilson County, Tennessee, is consistent with the observed bedrock features.

The left bank is moderately stable with some root protection from riparian trees. The bedrock at the bank toe provides natural armoring. However, the narrow riparian buffer and proximity of agricultural land limits root density. Some minor scour is visible at the bank toe. The bank height is moderate (3-6 feet) which reduces failure risk.

The left bank has only a single row of mature trees providing root protection. Between the tree trunks, herbaceous vegetation provides some ground cover but is dormant. The very narrow buffer on this side means that less than 70% of the bank has effective root zone protection. During leaf-off season, ground surface exposure is more visible.

Left bank transitions quickly from stream to agricultural field. Very narrow riparian buffer is the primary concern. The bedrock at the bank toe provides natural protection, but the lack of deep-rooted vegetation in the upper bank could lead to erosion during high flow events.

The right bank is moderately stable with a more developed wooded area extending upslope. The tree root networks provide protection, and the moderate slope angle helps maintain stability. Some minor erosion at the toe is visible but overall the bank appears intact.

The right bank has moderate vegetative protection with a mix of trees and understory shrubs. The winter dormancy reveals some bare soil areas and the understory is thin, but the tree canopy and root systems appear more extensive than the left bank. Coverage is estimated at approximately 60-70%.

Right bank has a wider riparian buffer zone than the left, with the wooded area extending upslope. The bank appears more stable than the left bank due to greater root density and wider vegetated area.

The left riparian buffer is extremely narrow, consisting of only a single row of trees (approximately 5-10 feet wide) before transitioning directly into an open agricultural field. For a channel width of approximately 6-8 feet, this represents roughly 0.33x to 1x channel width at best. The filtering function is severely compromised by this narrow buffer.

The right bank has a wider wooded riparian buffer that appears to extend 25-50 feet before transitioning to what may be agricultural land or a cleared area visible through the trees. This provides moderate buffering capacity, approximately 3-6x the channel width.

The left bank floodplain is dominated by agricultural grassland with almost no natural riparian vegetation. The right bank floodplain has moderate woody vegetation, but the overall floodplain condition is compromised by the agricultural encroachment on the left side. The ecosystem function is partially maintained by the right bank buffer but severely compromised on the left.

During winter leaf-off, current shade is minimal (under 25%). However, during growing season, the deciduous canopy from the trees along both banks would provide approximately 25-50% shade over the narrow channel. The left bank's single tree row and the right bank's wooded area combine to provide partial canopy coverage. The narrow channel width helps compensate for the limited buffer on the left.

The left bank represents a significant buffer deficiency. The flat agricultural field adjacent to the stream offers excellent restoration potential - establishing native trees and shrubs in a 30-60 foot buffer strip would be straightforward and highly beneficial. This should be flagged as a priority for TDEC MS4 permit section 4.2.5.4 compliance.

The bedrock-dominated substrate provides limited favorable surfaces for epifaunal colonization. While the bedrock crevices and loose cobble fragments offer some habitat, the smooth bedrock surfaces are poor colonization substrate. Minor undercut areas at bank edges and the few loose cobble/rubble fragments provide the primary favorable habitat, estimated at 20-40% of available substrate.

The loose cobble and gravel fragments on the bedrock surface show moderate embedding by fine sediment. Some areas have thin silt/mud deposits in low spots between bedrock ledges. Since this is a bedrock-controlled channel, the embeddedness scoring is less directly applicable, but the loose substrate that is present shows moderate fine sediment influence.

Pools are minimal at this flow level. The bedrock substrate limits natural pool formation except where scour has created shallow depressions. The entire bottom is largely discernible due to shallow water depth. No deep pools were observed in the visible reach.

Limited fish cover is available. The overhanging bank vegetation, minor undercut areas, and some root exposure along the banks provide the primary cover types. Deep pools, large woody debris, boulder cover, and macrophyte beds are absent or negligible. The bedrock substrate and low flow conditions severely limit fish habitat quality.

No barriers to fish movement are visible in this reach. However, the very low flow conditions during dry periods may create seasonal barriers to movement for larger fish. The bedrock substrate is generally flat and should allow fish passage during adequate flow conditions.

Very little large woody debris is visible in the channel. A few small branches and twigs are present, but no significant logs, rootwads, or debris jams were observed. The narrow channel and relatively thin riparian buffer on the left bank may limit LWD recruitment. The channel appears to have been naturally cleared of debris, possibly by high-flow events on the bedrock surface.

Three types of macroinvertebrate habitat are identifiable: loose gravel/cobble fragments on bedrock providing interstitial spaces, minor undercut bank areas, and leaf packs accumulating in bedrock depressions. However, submerged logs, fine woody debris, and boulder habitat are largely absent. The bedrock-dominated substrate limits the diversity of available microhabitats.

Score assigned at Group II level based on habitat potential rather than direct observation. The bedrock substrate with loose fragments, minor undercut banks, and leaf pack accumulations could support crayfish, some dragonfly/damselfly larvae, and potentially some EPT taxa in better-quality microhabitats.

No macroinvertebrates were directly observed in the imagery. Score is based on habitat assessment suggesting the substrate and water quality could support Group II (facultative) taxa. The bedrock substrate with some cobble and leaf packs, combined with fair water clarity, suggests moderate potential for macroinvertebrate diversity.

Suitable Habitat: No

The small headwater stream with bedrock substrate and limited habitat complexity is unlikely to support rare or threatened species. However, some limestone spring-fed streams in the Central Basin region of Tennessee can support sensitive species. A more detailed biological survey during appropriate season would be needed to confirm.

No wildlife directly observed. Some standing dead trees (snags) visible in the right bank riparian area could provide cavity nesting habitat. Winter conditions and the presence of the surveyor may have displaced any wildlife in the immediate area.

Water appears slightly turbid with a brownish tint, but objects are visible on the bottom in the shallow areas. This coloration may be influenced by tannins from leaf litter decomposition (winter season) or minor sediment disturbance from the wading surveyor. Overall water quality appears fair to good for a small agricultural stream during low-flow conditions.

No significant algal growth or macrophyte development is visible. Some dark organic staining on rocks may include minor biofilm, but there are no algal mats, green water coloration, or excessive plant growth. The winter season may limit algal expression, but the bedrock substrate and lack of soft sediment also limit macrophyte establishment.

No evidence of manure, livestock access, or waste discharge is visible at this location. The agricultural field on the left bank appears to be hay/pasture but no livestock are currently visible and no livestock access points or trampled areas are evident along the bank. Fencing may be present but is not clearly visible from this vantage point.

This is a warmwater stream with no impervious surfaces in the immediate vicinity. During summer, the narrow left-bank buffer and winter-bare canopy suggest significant solar heating potential. Expanding the riparian buffer on the left bank would improve shade coverage and reduce summer thermal stress. The bedrock substrate may also absorb and re-radiate heat during warm months. No groundwater seeps or spring inputs were observed that might provide thermal refugia.

No active permit compliance concerns related to recent disturbance. The inadequate riparian buffer on the left bank is a chronic condition rather than a recent disturbance event.

Terrestrial Invasives Assessment

Aquatic Invasives Assessment

Winter dormancy makes positive identification difficult. Some vine tangles visible in the understory may include Japanese honeysuckle based on persistent semi-evergreen leaves and growth habit. Some shrub forms on the right bank may be bush honeysuckle (Lonicera maackii) based on branching pattern, but identification confidence is low due to leaf-off conditions. A growing-season survey would be needed for definitive identification.