Black Branch 2

Small perennial stream passing through a concrete box culvert near the end of the Black Branch 251 reach. The culvert represents significant habitat degradation. Downstream of the culvert, the stream appears to have some natural character with wooded riparian corridor. Sediment impairment evident from turbid water and deposition within the culvert.

The stream at this location is entirely enclosed within a concrete box culvert, representing complete channelization at this point. The natural channel has been replaced with an engineered structure. Score of 2 reflects that while the culvert itself is not actively downcutting, the channel is 100% concrete-modified at this location. Downstream of the culvert, some natural channel characteristics appear present.

The box culvert constrains flood flows and disconnects the stream from its floodplain within the crossing. The culvert dimensions appear adequate for low to moderate flows but the structure inherently alters the natural hydrologic regime. Some incision may be present based on the depth of the culvert below grade.

Moderate sediment deposition observed across approximately 60-80% of the culvert floor. Fine sand and silt deposits 1-2 inches thick indicate active sediment transport from upstream. The flat concrete floor promotes deposition during low flow conditions. Score reflects moderate to heavy deposition within the culvert structure.

Within the box culvert, flow is dominated entirely by a single slow-shallow regime. The flat concrete floor and uniform cross-section preclude any velocity/depth diversity. No pools, riffles, or fast-deep areas possible within the concrete structure.

Water covers approximately 50-75% of the culvert floor width, with some areas of exposed sediment along the margins. The flow is shallow but present across most of the floor. The culvert is oversized relative to the current low flow condition.

No riffles possible within the concrete box culvert. The flat uniform floor eliminates all natural riffle-pool sequences. Completely flat water throughout the structure.

Rosgen classification is not determinable from inside the concrete box culvert. The culvert imposes an artificial straight, entrenched channel form. Based on the downstream view showing a small wooded stream with low gradient, the natural channel may be an E or C type, but this cannot be confirmed from this viewpoint. The upstream reach (scenes 1-50) would provide better geomorphic assessment. The fine sediment deposition within the culvert suggests the natural stream carries a significant fine sediment load.

Within the culvert, the left bank is a stable concrete wall with no erosion. However, beyond the culvert opening (visible in front view), the natural left bank appears moderately stable with vegetation cover but transitioning from concrete to natural conditions. The concrete wall provides complete stability within the crossing. Score reflects the mixed conditions of concrete stability at the crossing with some natural bank beyond.

Within the culvert, there is zero vegetative protection - the bank is entirely concrete. Outside the culvert, moderate deciduous tree and shrub cover is visible but in early spring condition with limited leaf coverage. The overall score reflects the significant length of unvegetated concrete wall within the culvert.

Left bank is entirely engineered concrete within the culvert. Transitions to natural bank conditions downstream of culvert outlet. Algae growth line on concrete wall indicates normal water level approximately 2 feet above current flow.

Right bank mirrors left bank conditions - concrete wall within culvert providing complete stability. Natural bank conditions visible beyond the culvert outlet appear moderately stable with woody vegetation. Score reflects the concrete stability within the crossing.

Same conditions as left bank - no vegetation within culvert, moderate vegetation coverage beyond culvert outlet in early spring condition.

Right bank conditions essentially identical to left bank - full concrete wall within culvert transitioning to natural bank downstream.

Within the culvert, there is no riparian zone. Beyond the culvert outlet (visible in front face), there appears to be a narrow wooded buffer with deciduous trees and shrubs, but the width appears limited. Some residential structures or development may be visible through the bare trees in the background, suggesting the buffer is narrow. Score of 3 reflects the complete absence of riparian function within the culvert and limited buffer beyond.

Similar to left side - no riparian function within culvert, limited wooded buffer visible beyond the culvert. Early spring conditions limit full assessment of vegetation density.

The culvert itself eliminates all floodplain vegetation function. Beyond the culvert, early spring deciduous trees and shrubs are present but appear to be a narrow corridor. The overall floodplain vegetation condition is marginal due to the culvert structure disrupting the riparian/floodplain corridor.

The concrete box culvert provides complete shade within its interior, but this is artificial shade from an engineered structure, not natural canopy. Beyond the culvert, early spring bare deciduous trees provide minimal shade. Overall canopy cover is very low for this reach location.

The box culvert represents a complete elimination of riparian buffer at this location. This is expected for a road crossing but should be documented. The road surface above contributes impervious surface runoff directly to the stream. Buffer restoration is limited to areas upstream and downstream of the culvert.

The concrete box culvert provides virtually no favorable substrate for epifaunal colonization. The smooth concrete walls and sediment-covered floor offer no structural complexity. No snags, logs, cobble, or other natural substrate is present within the culvert. Score of 1 reflects the complete absence of favorable habitat.

The concrete floor with fine sediment deposits provides no natural substrate for assessment. The hard concrete surface functions similar to bedrock with no root mats or vegetation possible. Score of 1 reflects the artificial substrate condition.

No pools present within the concrete box culvert. The flat uniform floor prevents any pool formation. The entire bottom is discernible through the shallow water. Score of 1.

Zero fish cover types present within the concrete box culvert. No logs, pools, overhanging vegetation, boulders, undercut banks, root mats, macrophytes, backwater pools, or riffles. The culvert is entirely devoid of fish cover.

The concrete box culvert is present within the reach. While the culvert does not appear to have a significant drop at the outlet (based on the front view showing the water surface transitioning relatively smoothly to the natural channel), the long smooth concrete floor with shallow water may impede fish movement during low flow periods. The culvert appears to be passable during moderate flows. Score of 5 reflects the culvert as a partial barrier.

No large woody debris present within the concrete box culvert. The culvert precludes any natural LWD recruitment or retention. Some debris visible at the upstream inlet but not within the assessed culvert section.

The concrete box culvert provides essentially no macroinvertebrate habitat. No fine woody debris, submerged logs, leaf packs, undercut banks, cobble, boulders, or coarse gravel present. The only potential habitat is the sediment layer on the concrete floor which may support limited tolerant organisms. Score of 1 reflects the complete absence of habitat diversity.

Habitat assessment only - no organisms directly observed. The concrete substrate with fine sediment would only support the most tolerant invertebrate communities.

No macroinvertebrates directly observed during assessment. The concrete culvert provides extremely poor habitat for aquatic invertebrates. Any organisms present would likely be limited to tolerant taxa (Group III) such as midges or aquatic worms in the sediment deposits. Score of 2 reflects the likely dominance of tolerant taxa based on available habitat.

Suitable Habitat: No

The concrete box culvert provides no suitable habitat for species of concern. The smooth concrete surfaces, shallow uniform flow, and lack of natural substrate or cover eliminate habitat value for virtually all aquatic species. The culvert may serve as a movement corridor but does not provide refuge or breeding habitat.

No wildlife observed within the culvert during assessment. The culvert environment is inhospitable for most aquatic and terrestrial wildlife. Barn swallows or similar species sometimes nest under bridge structures but no nesting evidence was observed on the concrete ceiling.

Water is moderately turbid with a brown coloration suggesting suspended sediment. Visibility appears to be approximately 0.5-1 foot based on the ability to partially see the concrete floor through the water. The turbidity may be elevated due to recent precipitation. No sheen, scum, or film observed on the water surface.

Green algae/moss growth is present on the concrete walls but this is typical for moist concrete surfaces in any culvert and does not necessarily indicate nutrient enrichment in the water column. No excessive algal growth in the water, no macrophytes, and no green coloration to the water itself. The brown color is from suspended sediment, not algae. Score of 7 reflects generally acceptable nutrient conditions based on visual assessment.

No evidence of manure, waste, or livestock access observed within or near the culvert. No waste discharge pipes visible. No sewage odor indicators.

Within the culvert, the stream is fully shaded by the concrete structure, which provides thermal isolation. However, the concrete floor and walls may absorb and radiate heat during summer months, potentially warming the water. The road surface above the culvert represents a source of heated stormwater runoff that would be discharged directly to the stream during rainfall events. The weepholes in the walls suggest subsurface connections that could provide some thermal buffering.

No active construction or disturbance observed. The existing culvert is an established infrastructure feature. Sediment accumulation within the culvert may warrant maintenance consideration.

Terrestrial Invasives Assessment

Aquatic Invasives Assessment

Assessment of invasive species is severely limited from inside the concrete box culvert. Vegetation visible beyond the culvert outlet in the front view includes deciduous trees and shrubs in early spring condition but species identification is not possible at this distance and with bare/partial leaf conditions. Confidence is low - adjacent scenes outside the culvert would be needed for proper invasive species assessment.

Concrete box culvert with cast-in-place walls and precast deck panels visible. Green algae/moss growth on lower portions of concrete walls indicates persistent moisture zone. Weepholes visible in both walls. Concrete is weathered but structurally intact. Downstream outlet shows sediment deposition and rock fragments at transition to natural channel.

Right culvert wall is cast-in-place concrete with clear panel joints and construction seams. Green algal/moss growth covers lower 40-50% of wall, indicating persistent moisture/flood level. Orange-brown mineral staining on upper wall. One circular weephole approximately 2 inches diameter visible near wall base. Concrete surface shows some spalling but is structurally sound.

Upstream view through box culvert shows full concrete enclosure. The culvert appears to be approximately 8-10 feet wide and 5-6 feet high based on the surveyor for scale. Left wall shows significant algae/moss growth and orange-brown iron/mineral staining. Concrete deck overhead shows panel joints. Upstream opening partially obstructed by debris. The culvert appears to be at least 30-40 feet long based on perspective.

Left culvert wall shows same construction as right wall - cast-in-place concrete with panel joints. Heavy green algae/moss colonization on lower portion. Orange-brown mineral/iron staining on upper portion and ceiling interface. Weephole visible near base. Some minor concrete spalling but no structural concerns evident.

Concrete deck underside shows construction joints between panels. Orange-brown staining likely from iron in groundwater seeping through joints. No significant cracking, delamination, or exposed rebar visible. Some minor surface weathering. The deck appears to carry a road above based on culvert configuration.

Concrete floor visible beneath thin sediment layer and shallow water. Floor-to-wall joint visible at right edge with algae colonization. Sediment layer appears to be 1-2 inches of fine sand and silt deposited across approximately 80% of the visible floor area. Some areas of bare concrete visible where water flow is slightly faster.