Black Branch 2

Small headwater stream in a rural agricultural/pastoral setting east of Nashville. The channel appears to support baseflow year-round based on flow presence during apparent dry winter conditions. Adjacent land use is primarily pasture/agriculture with some residential structures. No obvious impairment indicators observed at this location.

The channel appears largely natural with no visible engineered alterations or straightening. There is evidence of some bank erosion and scour, but no significant downcutting. The channel maintains connection to its floodplain on at least the right side. The pastoral land use and mowing close to the bank on the right side has likely reduced buffer function but not directly altered the channel form.

The channel shows slight incision with banks approximately 2-4 feet high. The right bank transitions gradually to the mowed floodplain, suggesting periodic flooding still occurs. No dams, withdrawals, or significant impervious area upstream apparent. Low banks relative to channel width suggest the floodplain is still somewhat accessible during higher flows.

Some fine sediment and gravel accumulation is visible in the channel, but the substrate is predominantly clean cobble and limestone fragments. Minor point bar development visible. Pools downstream show some sediment accumulation but are not filled. Overall sediment deposition appears within normal range for a small agricultural stream.

Three of four velocity/depth regimes are visible: slow-deep pools (front view), slow-shallow areas, and fast-shallow riffles (back view). The channel is too small and shallow to support fast-deep habitat. During higher flows, all four regimes may be present. The current low-flow conditions limit diversity.

Water is present throughout the visible reach but does not fill the full channel width. In the riffle areas (back view), significant substrate is exposed with thin flow over rock surfaces. In the pool area (front view), water fills more of the channel. Estimated 50-75% of the channel contains water at this low-flow period.

Riffles and pools appear to alternate at moderate frequency. The upstream view shows a riffle section while the downstream view shows a pool. Given the small channel width and apparent sinuosity, riffle spacing appears reasonable but not frequent. The riffle-to-riffle ratio is estimated at 7:1 to 15:1 channel widths.

This appears to be a small headwater stream with characteristics suggesting a Rosgen E-type channel: narrow, deep relative to width, sinuous planform, and cobble substrate with riffle-pool sequences. The low gradient and flood-prone character also align with E-type. However, confidence is low due to the limited view of the overall reach morphology from a single panorama. The channel could also be classified as B-type if gradient is moderate. The limestone substrate is characteristic of Middle Tennessee karst geology.

The left bank has dense shrubby vegetation and vine cover providing good root structure. Bank heights are moderate (3-6 ft in front view). Some root exposure visible but trees appear stable. The dense understory vegetation on this side provides significant bank protection. Overall moderately stable with good vegetative root coverage.

The left bank shows approximately 70-90% vegetation coverage including dense shrubs, vines, and trees. Some possible invasive vines are present (Japanese honeysuckle suspected in the dense vine tangles). Eastern red cedar and deciduous trees provide canopy. Minor disruption only. Generally good vegetative protection.

Left bank has the better riparian condition of the two banks. Dense shrub/vine coverage even during dormant season provides good bank stability. A red-roofed structure is visible approximately 100+ feet from the bank. Some potential invasive vine species present in the understory.

The right bank has reduced vegetative protection due to mowing/grazing extending close to the bank edge. Some scattered trees provide root stabilization in places, but there are areas of exposed soil and rock along the bank. The bank is generally low (under 3ft in the back view) which reduces erosion risk, but the lack of continuous root protection is a concern. Moderate stability overall.

The right bank has significant areas where mowed grass extends to or very near the bank edge, leaving limited woody riparian vegetation. Estimated 50-70% vegetative bank coverage. The grass provides some root protection but not the deep root structure of trees and shrubs. Scattered trees are present but do not form a continuous buffer. Obvious disruption from mowing/grazing activities.

Right bank lacks adequate riparian buffer. Mowed grass extends nearly to the channel edge. Scattered deciduous trees provide some protection but are not continuous. Bank erosion and bare soil exposure more pronounced on this side. An old barn/outbuilding is visible approximately 100+ feet from the bank.

The left bank riparian zone extends approximately 25-50 feet with dense shrub and vine vegetation before transitioning to agricultural/residential use. Given the channel width of approximately 3-5 feet, this represents roughly 5-10x the channel width, which is good. However, the vegetation composition is somewhat degraded with potential invasive species, reducing the quality of the buffer function.

The right bank has a very narrow and discontinuous riparian buffer. Mowed grass extends nearly to the bank edge in many areas. Scattered trees provide some overstory but there is little to no shrub layer or native understory buffer. The filtering function is significantly compromised with the mowed area extending to within feet of the channel.

The floodplain vegetation is significantly altered from natural conditions. The right bank floodplain is mowed grass, and while the left bank retains more natural vegetation, the overall floodplain is not in a natural state. Most native shrub and understory species have been removed or replaced by mowing on one side and potential invasives on the other.

During the current dormant season, canopy cover is approximately 20-30% from bare deciduous branches and scattered evergreens. During full leaf-out, canopy would be approximately 40-60% as the mature trees would provide significant coverage but gaps would remain, especially on the right bank side. For a warmwater stream, this moderate shade level is adequate but not optimal.

The right bank riparian buffer is severely compromised by mowing/grazing extending to the channel edge. TDEC MS4 permit section 4.2.5.4 requires minimum 30ft riparian buffers. Restoration potential is high on the right bank as simply ceasing mowing activities would allow natural regrowth. Active planting could accelerate restoration. The left bank buffer appears adequate.

Approximately 40-50% of visible substrate is favorable for colonization. Cobble and flat limestone provide some habitat for benthic organisms. Root exposure on the left bank and some undercut areas provide additional habitat. However, the channel is very small, limiting overall habitat diversity. Few logs or woody debris jams are present in the visible reach.

In the riffle area visible in the back view, cobble and gravel appear approximately 25-40% embedded in fine sediment. The limestone substrate is partially exposed with some interstitial spaces visible. In the pool area, substrate is less visible due to deeper water. Fine sediment accumulation is present but not overwhelming the coarse substrate.

Pools are present as seen in the front/downstream view, but they are shallow (likely less than 1-2 feet deep given the small channel size). The pool visible downstream appears to have water depth sufficient to obscure part of the bottom. Pool frequency appears moderate with riffles alternating. During higher flow, pools would likely be deeper and more functional.

Four cover types are visible: overhanging vegetation (branches extending over the channel), undercut banks (left bank), exposed root mats (left bank), and riffle habitat. Deep pools, logs/woody debris, and boulder cover are largely absent or minimal. The small channel size limits the diversity of cover types.

No barriers to fish movement are visible in the immediate reach. However, the very low water depth during this period could seasonally limit movement for larger fish. No culverts, dams, or drop structures are visible. The natural channel form appears unimpeded.

Very sparse large woody debris visible in the reach. A few small branches and twigs are present near the banks, but no significant LWD pieces or debris jams are observed. The channel may have been cleared or natural recruitment is limited due to the mowed condition on the right bank. No pool-forming or channel-spanning wood visible.

Three types of invertebrate habitat are present: cobble substrate in riffle areas, undercut banks with root exposure on the left bank, and coarse gravel in transition zones. Leaf packs and fine woody debris are minimal. The limestone cobble provides good attachment substrate, but the lack of diversity in organic habitat types (logs, leaf packs, woody debris) limits the overall score.

Score of 6 assigned based on habitat assessment rather than direct observation. The clean cobble substrate, clear water, and riffle-pool sequences suggest conditions suitable for facultative taxa. The agricultural land use and limited buffer on the right bank may reduce water quality periodically, potentially limiting sensitive species.

No macroinvertebrates were directly observed in the imagery, but habitat conditions suggest the stream could support Group II facultative organisms. The clean cobble substrate, flowing water, and lack of obvious pollution suggest moderate invertebrate community potential. Score assigned based on habitat quality rather than direct observation.

Suitable Habitat: No

The small headwater stream provides limited habitat for species of concern. The agricultural setting and disturbed buffer reduce habitat quality. However, the limestone substrate and clear baseflow could support some native fish and crayfish species during appropriate seasons.

No wildlife directly observed during this winter survey. The dormant season and human presence (wading surveyor) likely reduce wildlife visibility. Brush piles and rock accumulations on the left bank provide potential small mammal and reptile cover. The stream likely supports seasonal amphibian breeding given the pool habitat.

Water appears clear to slightly tinted in the riffle areas with substrate clearly visible through the water column. In the downstream pool, the water appears darker due to depth and reflection but does not appear turbid. No sheen, foam, or discoloration observed. During dry weather conditions, clarity appears good.

Water appears fairly clear with no visible macrophyte growth. Some minor algal film may be present on rocks (greenish tinge on some stones) but nothing excessive. No floating algae or algal mats observed. The agricultural land use could contribute nutrients, but visible indicators suggest moderate rather than excessive enrichment.

No direct evidence of manure or animal waste in the stream or on the banks. However, the mowed pastoral area on the right bank and the barn/outbuilding suggest agricultural use that could include livestock. No fencing to exclude livestock from the stream is visible, but no direct evidence of livestock access (trampled banks, manure) was observed at this location.

During summer, the right bank lacking canopy cover would expose the stream to significant solar heating. The bare deciduous trees currently provide minimal shade. When leafed out, the left bank trees would provide moderate shade. Buffer restoration on the right bank would significantly improve thermal conditions during warm months. No urban thermal impacts are apparent in this rural setting.

The ongoing removal of riparian vegetation through mowing/grazing on the right bank represents a potential compliance concern regarding TDEC MS4 buffer requirements. While this may be pre-existing agricultural use, any new development or MS4 permitted activities should require buffer restoration.

Terrestrial Invasives Assessment

Aquatic Invasives Assessment

Dense vine tangles on the left bank are suspected to include Japanese honeysuckle based on growth pattern, though positive identification is difficult during winter dormancy. Some evergreen vine growth visible in the left bank understory is consistent with Japanese honeysuckle retaining leaves through mild winters. Possible bush honeysuckle present in the understory. Confidence is low due to dormant season imagery; a growing season survey would provide better identification.