Black Branch 2

Small headwater stream in rural agricultural setting near Lebanon, TN (Wilson County). Channel is incised with limited riparian buffer and adjacent agricultural/residential land use. Habitat degradation evident from mowing to bank edge and loss of riparian zone. Bedrock exposure may indicate downcutting.

Channel appears natural with no direct structural alterations, but shows evidence of incision and downcutting to bedrock. The channel has cut down significantly, disconnecting from its floodplain. This is likely a response to changes in watershed hydrology from agricultural land use and impervious surfaces. Score of 5 reflects natural channel form but with significant geomorphic adjustment.

Channel is moderately incised with banks 3-6ft high relative to a narrow stream. The channel appears disconnected from its floodplain with flooding likely only during significant storm events. Agricultural land use changes and mowing to bank edge have likely accelerated runoff delivery.

Bedrock-dominated substrate with limited sediment deposition visible. The bedrock exposure actually suggests more erosion than deposition. Some fine sediment (mud/silt) visible in low spots but not excessive. The channel appears to be sediment-starved in areas with exposed bedrock.

At current low flow conditions, the stream is dominated by a single slow-shallow regime. The channel is extremely shallow with minimal water depth. No deep pools or fast-water habitats are visible. Limited flow diversity.

Water fills a relatively small portion of the channel at this low flow condition. Significant bedrock and bank substrate is exposed. Water appears to be present but confined to the lowest portion of the channel with much of the bed dry or barely wetted.

Stream appears predominantly flat with uniform shallow flow over bedrock. No distinct riffle-pool sequences visible. The bedrock substrate prevents formation of typical alluvial riffle-pool morphology. Flow is mostly uniform and sheet-like over exposed rock.

This small headwater stream appears to be a Rosgen G-type channel - an entrenched gully with bedrock exposure from downcutting. The channel has incised significantly into the landscape, likely in response to increased runoff from agricultural land conversion and residential development in the watershed. The bedrock exposure indicates the channel has cut down through alluvial material to the underlying limestone. This is a common condition in Middle Tennessee headwater streams subject to land use change. The F-type classification was also considered but the narrow width and gully-like nature suggest G-type is more appropriate.

Left bank is moderately steep with evidence of erosion and bare soil. Some dormant brush and shrub vegetation provides partial stabilization, but the bank shows signs of active erosion with exposed soil and scour. The incised nature of the channel creates high banks relative to the small stream. A thin strip of brush exists but is insufficient for full stabilization.

Left bank has approximately 50-60% vegetation coverage with dormant shrubs and herbaceous vegetation. Bare soil patches are visible, particularly near the water line. The vegetation appears to be a mix of native and potentially invasive species (difficult to determine in dormant season). Coverage is compromised.

Left bank (looking downstream) is the outer bank adjacent to agricultural fields. Dormant brush provides partial buffer but bank is actively eroding in sections. Some exposed bedrock at base of bank may provide natural resistance to further downcutting.

Right bank is moderately steep and directly adjacent to mowed lawn. The grass provides surface stabilization but shallow roots offer limited bank reinforcement below the top of bank. The steep angle and mowing to the bank edge result in moderate instability. No deep-rooted vegetation to stabilize the bank face below the turf layer.

Right bank is mowed to the edge with grass only. While the turf provides surface cover, there is no woody vegetation to provide root reinforcement of the bank. The maintained lawn represents an obvious disruption to natural riparian vegetation. Approximately 50-60% of the actual bank face appears vegetated (grass and some weeds).

Right bank is adjacent to maintained residential lawn that extends to the bank edge with no riparian buffer. Mowing to the edge removes any potential for woody vegetation establishment and limits bank stabilization capacity. This is a significant concern for long-term bank stability and riparian function.

Left bank has a narrow strip of dormant shrub and brush vegetation estimated at 10-25 feet before transitioning to open agricultural field. For a channel approximately 5-8ft wide, this represents roughly 2-3x channel width, but the vegetation quality is poor - mainly dormant weedy shrubs with no mature tree canopy. The narrow and degraded nature of this strip compromises filtering function.

Right bank has essentially no natural riparian buffer. Mowed lawn extends directly to the bank edge. There is no natural vegetation whatsoever between the maintained lawn and the stream channel. Filtering function is severely compromised.

Most trees and bushes are absent from the floodplain area. The right bank is entirely mowed lawn and the left bank has only a narrow strip of weedy brush. Floodplain vegetation is not in a natural state - it has been significantly altered by mowing, agriculture, and residential land use. A few scattered trees exist but do not form a functional riparian corridor.

The UP face confirms virtually no canopy cover over the stream at this location. The bare deciduous trees and absence of mature riparian trees mean even in full leaf, shade would be minimal. Currently in early spring with bare branches, shade is essentially zero. Even in summer, the few scattered trees would provide well under 25% shade cover.

Both banks fail to meet TDEC MS4 permit section 4.2.5.4 buffer requirements. The right bank is severely impacted by residential lawn maintenance extending to the bank edge. The left bank has a narrow, degraded buffer dominated by shrubs with no mature tree component. Both sides have high restoration potential - the right bank could benefit from cease-mowing zones and native tree/shrub planting, while the left bank could be enhanced with native tree planting and invasive removal.

Very limited favorable substrate for epifaunal colonization. The dominant bedrock substrate offers minimal habitat complexity. Some undercut banks may provide limited cover but there are virtually no logs, snags, cobble, or other favorable colonization substrates visible. The lack of riparian trees means no woody debris recruitment into the channel.

Using low gradient criteria. Substrate is primarily bedrock with mud/silt deposits in low areas. No gravel, sand, root mats, or submerged vegetation observed. The bedrock dominance limits habitat diversity. Some fine sediment (mud) overlies bedrock in places. Score of 3 reflects the mud/clay with minimal root mat presence.

Pools are essentially absent or extremely shallow. The bedrock substrate and low flow combine to create a nearly uniform shallow channel with no significant pool habitat. The entire bottom is discernible where water is present. Some very shallow ponded water visible but no functional pool habitat.

Very limited fish cover. Only undercut banks and some overhanging dormant vegetation provide potential cover. No logs, woody debris, deep pools, boulders, cobble, root mats, macrophyte beds, or backwater areas visible. The stream is too small and shallow to support significant fish populations.

No barriers to fish movement are visible in this immediate reach. However, the extremely shallow water conditions and bedrock substrate may create seasonal barriers during low flow. The stream may be too small to support significant fish movement regardless. Score of 7 accounts for seasonal low flow limitations.

Large woody debris is essentially absent from the channel. The lack of mature riparian trees means there is no recruitment source for LWD. Only minor small woody debris (twigs, small branches) from the few scattered trees is visible. No debris jams, no pool-forming wood, and no channel-spanning pieces observed.

Only 1-2 types of invertebrate habitat are present. Some undercut banks and minor leaf pack accumulation provide limited habitat. The bedrock substrate offers minimal interstitial spaces for colonization. Absence of cobble, logs, woody debris, and coarse gravel severely limits habitat diversity. The scoured bedrock substrate is poor for most macroinvertebrate communities.

Score of 6 assigned as a moderate estimate based on habitat potential for facultative organisms. Cannot confirm actual organisms from 360 imagery at this resolution and distance from the streambed.

No actual macroinvertebrates were directly observed in the imagery. Score is based on habitat assessment suggesting the limited but natural habitat could support Group II (facultative) organisms. The bedrock substrate with some undercut banks may support crayfish and some tolerant taxa. Assessment from imagery alone cannot confirm actual organism presence.

Suitable Habitat: No

The degraded habitat condition with minimal riparian buffer, lack of instream cover, and very small channel size limit the potential for species of concern. The stream is too small and degraded to support significant mussel populations or coldwater fisheries.

No wildlife directly observed during this survey point. The early spring dormant season, open landscape, and human presence (surveyor) may suppress visible wildlife activity. The habitat quality is generally poor for aquatic wildlife due to limited cover, shallow water, and minimal riparian buffer.

Water appears slightly turbid with a brownish color, possibly from fine sediment suspension or natural tannins. The extremely shallow depth makes clarity assessment difficult but the water is not excessively turbid. No oil sheen, film, or algal mats visible. The brown color may be partially from disturbed mud substrate. Score of 5 reflects moderate conditions.

No visible algal growth or macrophyte density issues. The early spring dormant season and low water temperatures likely suppress algal growth. No evidence of nutrient enrichment impacts visible at the time of survey. The adjacent agricultural land could contribute nutrients but no visible impacts are evident.

No direct evidence of manure, waste, or livestock access visible at this location. No livestock are observed in any direction. Adjacent agricultural fields appear to be crop fields rather than active pasture. No waste pipes or waste storage facilities visible. Score of 8 rather than 10 because agricultural fields in the vicinity could contribute runoff.

This reach has essentially no canopy cover providing thermal protection. In summer months, the fully exposed stream will experience significant solar heating. The shallow depth exacerbates thermal vulnerability. Even in the dormant season shown, bare trees provide no shade. Riparian buffer restoration with native trees would be the most effective thermal management action. The rural setting with low impervious surfaces reduces heated stormwater runoff concerns.

Riparian buffer on both sides fails to meet TDEC minimum standards. The right bank mowing to the channel edge is a chronic disturbance eliminating riparian function. While this is private residential property and may not be directly regulated under MS4 permits, it represents a significant water quality concern that could be addressed through outreach and voluntary buffer restoration programs.

Terrestrial Invasives Assessment

Aquatic Invasives Assessment

Confidence is low due to dormant season conditions making species identification very difficult. Some of the dense shrubby growth along the left bank could be bush honeysuckle based on growth form, and Japanese honeysuckle vine is common in Middle Tennessee riparian areas and may be present in the dormant tangles. The Callery pear (Bradford pear) blooming in the right bank view is possible but the white-flowering tree could also be a native species. A follow-up survey in full leaf season would be needed for definitive identification.