Fort Folly Habitat Recovery

Aquatic and Riparian Assessment

Wildlife

Several species of wildlife that warrant specific attention are found or have been found in the North River watershed: Atlantic salmon, American eels, and wood turtles.  Atlantic salmon (Salmo salar) Inner Bay of Fundy (iBoF) populations were listed as endangered under the Species at Risk Act in 2003 (DFO, 2010; SARA Registry, 2013a), and the species is considered to be extirpated from the Petitcodiac River system, except for those introduced in stocking programs (AMEC, 2005).  American eels (Anguilla rostrata) were designated as “Special Concern” by COSEWIC in 2006 (COSEWIC, 2006).  Their status was re-examined and raised to “Threatened” in May 2012 (COSEWIC, 2014). This species is being considered for listing under the federal Species at Risk Act, but currently it has no status (SARA Registry, 2013b). Wood turtles (Glyptemys insculpta) were designated as “Special Concern” by COSEWIC in 1996 which was raised to “Threatened” in 2007 (COSEWIC 2007; COSEWIC 2011). This species is listed as “threatened” under the Species at Risk Act (SARA Registry, 2012).  Guidelines for projects in areas with these species are in Appendix A.

The decline in numbers of iBoF salmon is a marked contrast to the abundance described by early settlers (Dunfield 1991).  Though numbers of this species had been decreasing for some time (Elson 1962) construction of the Moncton to Riverview causeway in 1968 eliminated fish passage for adult salmon and smolts and effectively (but for ongoing intervention) extirpated the species from a river system that represented 20% of the total iBoF population (Locke, et al. 2003).  Fort Folly Habitat Recovery has not encountered salmon in the course of its field work on the North River, but DFO has extensive records of interaction with salmon on the North River (Elson 1941).

Similarly American eels have not been encountered by Fort Folly Habitat Recovery along the North River, due in part to the limited amount of electrofishing done there (two sites in 2012).  However, historically they have been found in the North River watershed (Andrews 1943), and unlike salmon, eels were not excluded by the Moncton to Riverview  Causeway downstream on the Petitcodiac.  In fact while the causeway gates were closed eels were found to be the most abundant resident species upstream of the headpond (Flanagan 2001), and one of the dominant species within the headpond (Locke et al 2000). So though there is no recent data available on eel numbers within the North River watershed, unlike salmon there is no reason to think that they are absent.

Though no systematic targeted search have been made for Wood turtles on the North River, they have been encountered at several locations within the watershed during the course of conducting other field work. Due to their small home range, encounters with wood turtles are considered to be sensitive information, and so are being withheld here.

Water Quality

Water quality on the North River has been monitored by the Petitcodiac Watershed Alliance as part of their Petitcodiac basin wide water monitoring program, which has data going back to 2005 available online (Petitcodiac Watershed Alliance 2015).  The 2012 results are presented here (Petitcodiac Watershed Alliance 2012). They maintain a fixed monitoring site on the upstream side of the Route 885 bridge over the North River at Intervale, a short distance south of where the Trans-Canada Highway crosses the river. As a single site within the watershed there is a limited amount that can be concluded from it, however being located near the point where the North meets the Anagance and becomes the Petitcodiac, it does provide useful insight to the watershed upstream.  The fact this location has been monitored since 2005 also provides some significant time depth.  Conductivity readings for the North are quite high compared to both the Little and the Pollett, however it is likely that this reflects in part the location of the sampling site along the North, a short distance upstream of the mouth of Salt Springs Brook.  As a consequence, while obviously not directly influenced by Salt Springs Brook itself, presumably there is related substrate in the area that is contributing to the elevated conductivity readings.

Table 4-2:  Water Quality on the North River in 2012 (Petitcodiac Watershed Alliance 2012)

Rapid Geomorphic Assessment (RGA) and Rapid Stream Assessment (RSAT)

The following is taken from the report prepared by Parish Geomorphic and is based upon the rapid geomorphic assessments (RGAs) and rapid site assessments (RSATs) Fort Folly Habitat Recovery conducted on the North River in 2012.

The North River was segmented into 138 sub‐reaches within six main reaches. The assessment of the North River started just east of Route 126 at Indian Mountain and ended at the confluence with the Anagance River in Petitcodiac. The total length of river covered was approximately 46 km.

Geomorphic Analysis

The RGA and RSAT data were used to determine the geomorphic condition and stability of the assessed sections of North River. In order to interpret the geomorphic data, the watercourses are highlighted on their respective maps according to the sub‐reach stability. A bar graph is also associated with each sub‐reach and illustrates the dominant geomorphic process. The geomorphic processes identified included aggradation, degradation, channel widening, and planform adjustment.

Aggradation

Channel aggradation may occur when there has been a significant decrease in flows, a significant increase in sediment supply, or a significant decrease in slope due to irregular meander migrations. Depending on upstream processes and the boundary conditions of the reach, channel widening may occur in association with channel aggradation.

Indicators of agradation

Shallow pool depths

  • Abundant sediment deposition on side bars and non‐vegetated mid‐channel bars, extensive sediment deposition at obstructions, channel constrictions, at the upstream end of tight meander bends, and in the overbank zone
  • Most of the channel bed is exposed during typical low flow periods
  • High frequency of debris jams
  • Coarse gravels, cobbles, and boulders may be embedded with sand/silt and fine gravel
  • Lateral migration of thalweg
  • Soft, unconsolidated bed
  • Mid‐channel bars
  • Deposition on point bars

Degradation

The process by which a stream’s gradient becomes less steep, due to the erosion of sediment from the stream bed. Bed lowering can move in both an upstream direction (as a headcut or nick point) and/or downstream. This can occur from a rapid removal of streambed material due to an increase in discharge, water velocity, or a decrease in sediment supply.

Indicators of degradation are:

  • Elevated tree roots
  • Bank height increases as you move downstream
  • Absence of depositional features such as bars
  • Head cutting of the channel bed
  • Cut face on bars

Channel worn into undisturbed overburden/bedrock

Widening

When the stream becomes incapable of transporting its sediment load, sediments collect on the stream bed, forming mid‐channel bars that concentrate flows into both banks, and lead to a wider channel. Streams that score poorly under channel aggradation may also score poorly for the channel widening parameter. Channels also become over‐widened due to an increase in flows or to a decrease in sediment supply, which is not necessarily related to bed aggradation but may be seen in association with degradation. In these cases widening is the dominant process.

Indicators of widening include:

  • Active undermining of bank vegetation on both sides of the channel; many unstable bank overhangs that have little vegetation holding soils together;
  • Erosion on both right and left banks in riffle sections;
  • Recently exposed tree roots;
  • Fracture lines at the top of the bank that appear as cracks parallel to the river; evidence of landslides and mass failures;
  • Deposition of mid‐channel bars and shoals
  • Urbanization and storm water outfalls leading to higher rate and duration of runoff and channel enlargement typically in smaller watersheds with a high percentage (>10%) of impervious surface (urban land use).

Planform Adjustment

Changes to the planform can be the result of a straightened channel imposed on the river through different channel management activities, or a channel response to other  adjustment processes such as aggradation and widening. This migration process will start with degradation if the channel slope is increased or with aggradation if the slope is decreased.

Indicators of planform change are:

  • Flood chutes, which are longitudinal depressions where the stream has straightened and cut a more direct route usually across the inside of a meander bend;
  • Channel avulsions, where the stream has suddenly abandoned a previous channel alignment;
  • Change or loss in bed form structure, sometimes resulting in a mix of plane bed and pool‐riffle forms;
  • Island formation and/or multiple thread channels;
  • Additional large deposition and scour features in the channel length typically occupied by a single riffle/pool sequence (may result from the lateral extension of meander bends).
  • Thalweg not lined up with planform. In meandering streams the thalweg typically travels from the outside of a meander bend to the outside of the next meander bend. During planform adjustments, the thalweg may not line up with this pattern.

Watercourse Channel Stability

A key piece of data obtained from the Rapid Geomorphic Assessment is stream geomorphic condition based on the degree of departure of the channel from its reference stream type, which is evaluated by the magnitude and combination of adjustments that are underway in the stream channel. With respect to stream equilibrium and natural variability, the degree of departure is captured by the following three terms:

In Regime: A stream reach in reference and good condition that is in dynamic equilibrium which may involve localized, insignificant to minimal change to its shape or location while maintaining the fluvial processes and functions of its watershed over time and within the range of natural variability.

In Adjustment: A stream reach in fair condition that has experienced major change in channel form and fluvial processes outside the expected range of natural variability; and may be poised for additional adjustment with future flooding or changes in watershed inputs that could change the stream type.

Transitional or Stressed: Refers to a stream experiencing extreme adjustment outside the expected range of natural variability for the reference stream type; likely exhibiting a new stream type; and is expected to continue to adjust, either evolving back to the historic reference stream type or to a new stream type consistent with watershed inputs and boundary conditions.

 


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