0
Alder Brook
1
Acknowledgements The Alder Brook Management Plan is a sub-section of ACAP Saint John’s ‘Investing in Saint John’s Urban Watercourses’ initiative. The project represents a collaboration of numerous individuals and organizations who share a common vision of protecting the immense natural capital that exists within our city. We would like to say a special thank you to the New Brunswick Environmental Trust Fund, the New Brunswick Wildlife Trust Fund, Unilever Inc., and Clow Canada for their generous financial contributions to this important community endeavor. Contributions from the City of Saint John included those of Yves Leger (GIS Planning and Developing Branch) who contributed the aerial photographs used in this project, and Susan Fitzpatrick (Municipal Operations) who provided the truck to remove litter and debris collected during a cleanup and physical assessment of the watercourse. Thanks also to Helene Rioux from Service New Brunswick for information on property ownership, to Ryan MacAllister from the University of New Brunswick (Saint John) CURA for assistance with the concepts or urban planning and green spaces, and to NB Environment Minister Trevor Holder for sharing his experiences and vision of the Alder Brook watershed. Lastly thanks to the crew who assisted us with the ‘beginning-to-end’ cleanup of Alder Brook. Ashley Sproul Roshini Cassie Ryan MacAllister
Alder Brook
2
Executive Summary The Alder Brook watershed is a 245 ha drainage basin located in north-central Saint John, New Brunswick. It is a moderately urbanized area comprised of residential, institutional and recreational lands. The watercourse extends from Crescent Lake to Brothers Cove at a length of 2.5 km. Fieldwork was conducted along the entire length of the stream and a comprehensive set of observations on current conditions was created. Using these observations as a base, recommendations for the remediation and conservation of key watershed areas were established. Key recommendations include a new water control system at the outlet of Crescent Lake, improved pooling and fish passage along upper Alder Brook, and mitigating erosion and run-off associated with new developments.
Alder Brook
3
Table of Contents Backgrounder on Watershed Management
4
Introduction
5
Methods
5
Results
6
Introduction and Suggested Management Options for the Alder Brook Watercourse Section 1 Section 2 Section 3 Section 4 Section 5 Section 6
10 11 13 18 19 23 25
Summary of Management Options
27
Alder Brook
4
Backgrounder on Watershed Management A watershed is a distinct geographical area in which all water within its boundaries drains into a common watercourse (i.e. river, stream, lake, etc). Watershed management utilizes these precise geographic limits to form a finite working area within which recommendations can be made to conserve or enhance desirable features. Typically, watershed management plans focus on identifying existing or potential threats to the environmental integrity of the watershed. A watershed is bound by the geology of the area with the underlying bedrock, contours, and elevation of the earth ultimately determining the natural morphology and flow rates of the watercourse. The shape of a stream may be affected by natural events (such as heavy rainfalls, spring freshets and beaver dams), however it is anthropogenic activities such as road construction and residential and commercial/industrial developments that result in the most substantial changes. The same can be said for the chemical composition of a watercourse, with either point or non-point source pollutants often degrading its suitability to sustain aquatic life or to provide safe drinking or recreational waters for humans. Developing watershed management plans requires a detailed assessment of both the watershed itself, and the watercourse(s) it supports. Assessing the features and existing activities within a watershed often provides trained personnel with an immediate inventory of how the watershed benefits the community, which areas are most worth conserving, which areas are in need of remediation or enhancement, and who within the community might be willing to assist in developing and implementing the final plan. Assessing the chemical and physical attributes of the watercourse itself often provides insights into problems that are difficult to detect with the naked eye. Analysis of fecal coliform bacteria, phosphates and nitrates may highlight the occurrence of pollutants such as sewage or fertilizers. Information like this can be readily applied to a management plan to further pinpoint the source, and correct it. Ultimately, it is the responsibility of those developing the management plan to ensure the community has an opportunity to express its interests and ideas for how a given watershed should be used, developed, or conserved. This concept is especially true in urban settings where a diverse array of potential uses may exist. Engaging all interested parties in developing the final recommendations for a given watershed may prevent unnecessary conflicts.
Alder Brook
5
Introduction and Methods Saint John, New Brunswick possesses an abundance of water resources, which form an intricate web of fish and wildlife habitat amidst an urban setting. This rich natural capital has historically been used by residents and tourists for fishing, hunting, swimming, canoeing, hiking and bird watching, in addition to the immeasurable aesthetic value it has added to our quality of life. Saint John, like other urban areas, has altered the morphological characteristics of its watersheds through residential, commercial and industrial developments. Such developments are proven environmental stressors that can negatively impact the water quality, quantity and hydraulics of the watercourse, as well as the quality and abundance of plant, animal and fish habitat. The Urban Watershed Management project set out to survey four major watersheds (and their respective watercourses) in the greater Saint John area observing both the positive features to be preserved and utilized and negative features which need improvement. Topographic maps and aerial photos were used to identify four major urban watersheds in Saint John including Marsh Creek, Hazen Creek, Little River and Alder Brook. Each watershed was subdivided into distinct sub-watersheds based on existing tributaries. Each watercourse (including streams, lakes, ponds etc.) were assessed by examining observing aerial photos and by physically walking and making first hand observations of specific sites. These observations formed the basis of the draft management plans (including suggested management options) that will be presented to stakeholders for review and editing. Watercourses were assessed for their general condition, substrate type, shape, water flow, and riparian vegetation. A “Sport Track Map, Magellan” Global Positioning System receiver was used to mark the beginning and end of each walkthrough as well as important and interesting features along the watercourse. These notes and GPS points were then entered into a computer to assist in developing digitized maps of the watershed. Property maps and landowner information were obtained using the “Planet” program obtained via a demo account provided by SNB.
Alder Brook
6
Alder Brook Watershed The Alder Brook watershed, located in Milledgeville, Saint John, NB encompasses a total land area of 245 hectares (Figures 1 & 2). The watershed contains one predominant stream (Alder Brook), which originates at the southern end of Crescent Lake and extends 2.5 km to its terminus in Brothers Cove of the Kennebecasis River. Alder Brook also receives point source inputs of water from a culvert which carries intermittent runoff from a hillside near the Saint John Regional Hospital, and a small, permanent, spring fed tributary which drains from a steep northern slope in its lower section.
Figure 1: The location of Alder Brook within the City of Saint John
Alder Brook
7
Figure 2: Aerial Photo of the Alder Brook watershed, outlined in light blue, and Alder brook, outlined in dark blue.
The Alder Brook watershed, defined by a narrow corridor with moderate to steep slopes, has a maximum elevation 109 metres above sea level (Figure 3). The Alder Brook watershed is a true multi-use urban area with residential, municipal, commercial and recreational infrastructures interspersed throughout a landmass, which is vegetated on approximately 70% of its area (Figure 2). The northeastern range of the watershed occurs within the boundaries of Rockwood Park, the largest municipal park in Canada (Figure 4). This portion of the park consists of a golf course, which includes an aquatic driving range at Crescent Lake. The northwestern portion contains the University of New Brunswick Saint John (UNBSJ) and the Saint John Regional Hospital. The central (southeastern) region is comprised of sparse residential developments and a commercial Garden Center and
Alder Brook
8
landscaping operation. The southwestern region of the watershed contains subdivisions and apartments amidst well-forested parcels of land.
Figure 3: Topography of Alder Brook watershed
Alder Brook
9
Figure 4: Properties and owners within the Alder Brook watershed
ÂĽ
n
Alder Brook
Âľ
10
Alder Brook Watercourse The major watercourse contained within the Alder brook watershed can be divided into six distinct sections based upon physical characteristics (Figure 5).
Figure 5: An aerial view of Alder Brook divided into each of the six distinct sections.
ÂĽ
n
Alder Brook
Âľ
11
Section 1 Crescent Lake forms the headwaters of Alder Brook (Figure 6). The lake has an area of 7.65 hectares, with some 1.7 km of shoreline (Figure 7). Crescent Lake has longstanding recreational value both as an aquatic driving range and for recreational anglers in pursuit of Brook Trout. Aesthetically, the lake serves as a scenic backdrop for the Rockwood Park Golf Course with clear waters and an abundance of shoreline vegetation. The lake is relatively free of litter, with the exception of small amounts of Styrofoam, escaped floating golf balls, and fast food containers, as well as discarded fishing tackle including bobbers, hooks and monofilament line. Both brown trout and lake trout have been fished in this lake indicating cool, deep water. Other wildlife found in the lake include a variety of frogs and painted turtles.
Figure 6: Location of Section 1 in Alder Brook
Alder Brook
12
Figure 7: Left: View of Crescent Lake as seen from the Rockwood Park golf course. Right: Crescent Lake’s shoreline visible beyond the wooden structure used to collect floating golf balls from the aquatic driving range Management Recommendations The stature of Crescent Lake as a component of Rockwood Park has provided a measure of protection against commercial or residential developments. Furthermore, Rockwood Park does not administer pesticides to its properties (Bernie Morrison, City of Saint John, personal communication), and as such, acts as a green barrier against such chemicals. It is recommended that the watershed surrounding Crescent Lake be maintained at its present state. Annual cleanups of debris from the shoreline of Crescent Lake would minimize the risks to wildlife associated with discarded fishing tackle and plastic bags.
¥
n
Alder Brook
µ
13
Section 2 This section of Alder Brook (Figure 8) begins as a water control structure at the south end of Crescent Lake, and continues for approximately 0.7 km until it disappears beneath University Avenue. The structure, which is approximately 60 cm in diameter, is fitted with metal bars to prevent large objects from entering the culvert. This structure poses a significant barrier to fish passage, and is routinely clogged with woody debris and leaves (Figure 9). The bank surrounding the culvert is composed of gabions (rubble sized beach stones encased in wire). When the culvert is clogged with debris, the lake water actually flows through the adjoining rock substrate at a greater rate than through the culvert itself.
Figure 8: Location of Section 2 in Alder Brook
Alder Brook
14
Figure 9: Water control structure at outlet of Crescent Lake. Photo on left shows woody debris and leaves cogging the entrance. Lake water flows through the wire encased rubble when the outlet pipe is clogged (right). The structure poses a significant barrier to fish passage.
The water control structure directs flow through a culvert beneath the Sandy Point Road. Alder Brook emerges (begins) via this culvert following a small drop (Figure 10, left). Fish (cyprinids) were observed at the mouth of the culvert. This section of Alder Brook consists of mostly riffles and runs, with a limited number of pools. The stream substrate is dominated by gravel, cobble and rocks, and is suitable habitat for brook trout. A large pool (Figure 10, center), located some 200 m downstream of the Sandy Point Road culvert, exists due to an old, man-made dam. The dam, created for irrigation purposes, was comprised of wood laced with sheets of landscaping plastic and Styrofoam. Bits of the plastic and Styrofoam were torn off and floating downstream catching on rocks and twigs during their travels. A degraded wooden structure containing the old electric irrigation pump still exists beside the pool (Figure 10, right).
Alder Brook
15
Figure 10: Left: A hanging culvert, emerging from beneath the Sandy Point Road, marks the beginning of Alder Brook. Center: Pool habitat in Alder Brook adjacent to University Avenue. Right: Wooden structure housing an old electric pump used to transport water from Alder Brook for irrigation purposes.
The pool contains an abundance of aquatic vegetation, with a marshy parameter comprised of common cattails, marsh grasses, and golden rod. This large pool is almost a pond habitat, with evidence of deer tracks, and either coyote or fox scat. Both fish and waterfowl were observed. The riparian zone in this upper portion of Section 1 is quite wet and consists mainly of cedar, bittersweet nightshade, birch and an overabundance of golden rod. The dense canopy provides overhanging protection for aquatic organisms, and likely prevents its use for recreational purposes, such as hiking. The dense riparian vegetation also appears to act as an effective buffer between the stream and the road, catching the majority of litter and debris before it reaches the stream. A stream cleanup (conducted on August 11, 2006) found much of the debris located in close vicinity to the stream to be more than ten years old, suggesting only a small amount of garbage reaches the stream each year. The riparian zone of Alder Brook changes below the man-made dam. The banks were still comprised of mixed woods but with fewer cedars and more deciduous trees. Ground cover contained more ferns and no goldenrod. The banks of the stream became steep with some large rocks and bedrock emerging from soil cover (Figure 11, left).
Alder Brook
16
Figure 11: Large rocks form a substantial component of the riparian zone of the middle stretch of Alder Brook (left), as well as the in-stream substrate (right). The stream eventually meets with the edge of University Avenue at a juncture that contains a culvert draining portions of UNB Saint John and the Saint John Regional Hospital. A small pool with gravel substrate has formed at this point. The stream continues along University Avenue, passing through a new and unfinished development. The new development includes runoff from the former Howe’s Lake City of Saint John dumpsite as well as silt and sediment passing through failed silt fencing (Figure 12). Alder Brook continues alongside University Avenue until it reaches the Canadian Blood Services where it then flows underground.
Figure 12: Sediment-laden water enters Alder Brook from the hillside below the former City of Saint John dumpsite at Howe’s Lake. The water, which freely flows beside University Avenue, is being investigated for potentially hazardous chemicals leaching from the dumpsite.
Alder Brook
17
Management Recommendations This upper section of Alder Brook possesses a unique opportunity to conduct fish habitat improvement work, possibly in conjunction with the Canadian Rivers Institute associated with the nearby University of New Brunswick. Specifically, an annual field course could be conducted whereby fish habitat and water quality parameters are quantified and qualified; a number of improvement options are produced, debated, decided upon, and ultimately implemented in the field. The course could monitor characteristics of the brook trout population each year and determine the success of their efforts. Specific habitat improvement options identified in this report include increasing the amount of pool habitat, improving fish passage through the water control structure at Crescent Lake, at the man-made irrigation dam, and through the cascades amidst the section dominated by bedrock substrates. Removing the Styrofoam and plastic imbedded in the irrigation dam as well as the old pump housing itself would reduce the amount of debris entering the brook. The obvious degradation of water quality and fish habitat associated with the runoff from the former Howe’s Lake dumpsite needs to be addressed. Watercourses in Saint John have been subjected to anthropogenic stresses (including physical disruption, siltation and chemical inputs) for far too long. The activities associated with this new development should be closely monitored to assist the proponent with maintaining the environmental integrity of Alder Brook. This construction has also removed some of the vegetative cover from the riparian zone along this section that should be replaced upon the completion of activities. Large, native trees should be planted along sections where openings in the vegetative cover occur next to University Avenue. The vegetation has proven to be an effective natural barrier against litter, debris and human activities near the watercourse. The terminus of Section 2 occurs at a culvert that collects debris. This needs to be cleared on a regular basis to ensure fish passage and prevent bank erosion from water backing up during heavy flow periods. Overall, the watershed in this section requires little in terms of remediation. The greatest threat comes from contaminants in the old Howe’s Lake dumpsite, and from residential developments. Ensuring that existing guidelines for working near watercourses are followed should maintain the quality of this brook.
¥
n Alder Brook
µ
18
Section 3 This portion of Alder Brook flows underground for approximately 1 km (Figure 13). The culverts are imbedded deep enough to allow for fish passage, even during low flow periods. Options for this section are limited to ensuring the ends of the culverts are kept clear of debris and other obstructions.
Figure 13: Location of Section 3 in Alder Brook
ÂĽ
n
Alder Brook
Âľ
19
Section 4 This portion of Alder Brook (Figure 14) emerges from two culverts beneath University Avenue (Figure 15). The banks of this section run between three residential apartment buildings and their parking lots. The riparian zone contains herbaceous vegetation (including raspberry) and a few trees, which provides stability to the bank but little canopy cover. The streambed at this point consisted of gravel, rock, silt, and clay.
Figure 14: Location of Section 4 in Alder Brook
Alder Brook
20
Figure 15: Alder brook emerging from two large concrete culverts beneath University Avenue This section of Alder Brook became quite linear as it flowed through a grassy swales, cattails and alder bushes (Figure 16, left). The bottom substrate varied between hard clay and fine, unconsolidated sediments. Water velocity through this section was slower than in Sections 1 and 2, but water depth was greater, occasionally reaching 1 m. Dense, in-stream aquatic vegetation resulted in narrow channels of unobstructed water flow, with the occasional opening creating pool-type habitats which held schools of 20 – 50 cyprinids. Evidence of considerable wildlife use was observed throughout this area, and included signs of deer, muskrat, beaver, raccoons and waterfowl. A beaver dam marked the end of this section of Alder Brook (Figure 16, right). The dam created the largest pool habitat in the watercourse, and was being used as a swimming hole at the time of this survey (August 2006). The right stream bank (looking upstream) near the pool was stripped of all trees, and appeared to be associated with a house in an adjacent subdivision.
Management Recommendations This section of Alder Brook flows through a secluded patch of grasses and shrubs, which is surrounded by mature forest. The primary recommendation for this section is to maintain the vegetative integrity of the extended riparian zone. However, a proposed (northern variant) route for the Liquefied Natural Gas (LNG) pipeline cuts through the unspoiled
Alder Brook
21
Figure 16: Left: Middle section of Alder Brook showing linear morphology amidst an abundance of grasses and shrubs. An abundance of wildlife in this section was clearly evident. Right: A swimming hole, used by children in nearby residences, was created by a beaver dam at the end of Section 4 of Alder Brook. This swimming hole is also the largest pool habitat in the watercourse. wooded sections of the watershed (Figure 17). The removal of large trees, coupled with the unfettered access to Alder Brook that will accompany the required right-of-way for the LNG pipeline will undoubtedly reduce the existing environmental integrity and spectacular natural capital in this portion of the watershed. Specifically, the LNG right-of-way will fragment the contiguous wooded areas that exist on the northern slope of the watershed. Given the amount of large, wooded habitat in this portion of the watershed, it is recommended that the LNG right-of-way not pass through this area. However, if the LNG pipeline cuts through this portion of the watershed, measures must be taken to ensure vehicle traffic (especially ATV’s) is prevented from using the right-of-way. Such vehicles would reduce the physical integrity of the steep northern slope, and would cause considerable damage to the soft streambed. Noise pollution from such activity would also reduce the quality of life for residents of the High Ridge Road area, and could disturb any wildlife using the area for breeding. The proposed right of way would also allow for easy migration of many invasive plant species (such as purple loosestrife, Indian balsam, and Japanese knotweed). Given the opportunity these invasive plant species could strongly compete with native species (which currently form the riparian vegetation) for nutrients and light, resulting in a decrease of the native species.
Alder Brook
22
Figure 17: Proposed LNG pipeline corridor options, the northern corridor, variant 1, cuts though Alder Brook at two distinct locations Maintaining the existing natural capital in this section of the watershed should be a top priority for urban planners given that the number of watercourses in urban Saint John that possess the ability to provide diverse wildlife habitat and recreational opportunities for our youth are in decline. It should also be noted that any pollutants entering the upstream watercourse (for example from the old Howe’s Lake dump site) could have an adverse affect on persons using Alder Brook as a swimming hole. It is imperative that regulatory agencies ensure no chemical pollutants, especially toxins that could affect human health, be allowed to enter the Alder Brook watershed.
ÂĽ
n
Alder Brook
Âľ
23
Section 5 This lower section of Alder Brook (Figure 18) consists of numerous cascades and waterfalls that descend through large rock and rubble (Figure 19, left). There is an abundance of pool habitat, with some cobble and gravel substrates; however, the drops created by the large rocks create numerous challenges for fish passage. There are a few small rock dams built by an unknown source that create some pool habitat but add to the problems of fish passage (Figure 19, center). In-stream debris was also evident in several portions of the stream (Figure 19, right). In many cases this debris increased in- stream cover for fish, and reduced water velocity in areas of steep gradients; however, in some cases, excessive debris formed a dam that likely inhibited fish passage. A small spring fed tributary, containing clear, cold water, flows into this section of Alder Brook from the steep northern slope. The unspoiled riparian zone, with its abundance of mature cedar, spruce, ash and birch, makes for highly scenic settings. This portion of Alder Brook has excellent canopy cover and is secluded from adjacent housing developments by a wide, tree-covered buffer zone.
Figure 18: Position of Section 5 in Alder Brook
Alder Brook
24
Figure 19: Left: A waterfall cascades through bedrock in Alder Brook. Center: Small rock dams (built by unknown individuals) increase pool habitat but reduce to fish passage. Right: Woody debris frequently collects amidst the rocks and rubble, increasing pool habitat and providing in-stream cover for fish.
Management Recommendations The lower section of Alder Brook is one of the most scenic watercourses in Saint John. The well-treed riparian and buffer zones, which are natural extensions of those in Section 4, are covered with white-tailed deer tracks and game trails. As with the previous section, maintaining the environmental integrity of this watershed is vital to conserving the invaluable natural capital in this region of Saint John. This is especially true of the small cold spring that feeds into Alder Brook, which undoubtedly helps to maintain suitable temperatures for brook trout. A well-designed fish habitat improvement project would be needed to increase fish passage without detracting from the natural aesthetics of the watercourse. It is recommended that any such work be conducted with the utmost care and planning to ensure the existing cascades and waterfalls are not eliminated.
ÂĽ
n
Alder Brook
Âľ
25
Section 6 The terminus of Alder Brook (Figure 20) occurs where the watercourse crosses under Kennebecasis Drive, to drain into Brothers Cove of the Kennebecasis River. The area was previously inhabited with beavers, which blocked off the drainage culvert with a dam (Figure 21). This blockage has caused the watercourse to widen and increase in depth, with reduced water velocity. The bottom substrate consisted of an abundance of detritus, silt, and sand. Numerous fish (cyprinids) were observed in this section, but fish passage to the river would be difficult due to the beaver dam.
Figure 20: Location of Section 4 in Alder Brook
Alder Brook
26
Figure 21: A beaver dam, which continues to collect debris, blocks the mouth of Alder Brook. The dam has caused Alder Brook’s stream banks to widen and the flow to slow.
Management Recommendations This portion of Alder Brook is the most critical for the passage of anadromous fishes. As such, the blockage caused by the beaver dam should be removed and maintained such that fish passage is possible year round.
¥
n
Alder Brook
µ
27
Summary of Watershed Management Options Stream Section
Location
Recommendations
1
Watershed around Crescent Lake
Maintain existing green zone around lake. Conduct annual cleanups of litter along shoreline
2
Water control structure at outlet to Crescent Lake
Design and construct structure to enable fish passage to and from Crescent Lake
2
Throughout entire section
Increase number of pools and improve fish passage though in stream structures
2
Pond created by wooden dam
Remove old irrigation, pump structure
2
New Development
Monitor new development and plant native tress where erosion may become a problem
4
Entire section
Monitor for toxins
5
Entire section
Develop a plan to improve in stream fish habitat and preserve current condition of this section
Outlet to Brothers Cove
Remove debris inhibiting fish passage and maintain improved
6
ÂĽ
n
Alder Brook
Âľ