· WC1: The channel morphology site erosion is evident throughout this · EC1: The channel morphology site length was 56 m. This site was the reach. Instream cover consisted of length was 40 m. This site is heavily furthest downstream site sampled extensive woody debris. forested. Connection to the and is located just south of where the River at this location is blocked by the creek flows into the culvert that runs · EC4: The channel morphology site raised recreational trail. Ponded under the RCMP complex. The creek length was 40 m. The site was heavily water was observed upstream of the banks at this site are forested with a forested with a narrow channel cross- raised recreational trail both during thin section of riparian woodland. section. The flow regime can be baseflow and peak flow conditions. Exposed soils along the banks and characterized as having shallow water erosion sites are evident throughout depth but with higher flow velocities Photographic logs of each assessment site this reach. than EC5 due to the reduced channel (EC5- EC1) are included in Appendix D. width. Stream banks have improved General Findings Photographic logs of each assessment site vegetative cover and overall erosion (WC5- WC1) are included in Appendix D. sites are reduced, however The following sections describe the undercutting of the banks is evident. general findings of the DST (2013) Aquatic Eastern Creek Habitat Assessment Report Appendix D. · EC5: The channel morphology site · EC3: The channel morphology site Table 19 presents a summary of key length was 73 m. This site is the most length was 74 m. This site is a side findings and individual results. upstream site and was located north tributary to the main channel (flowing of the Rockcliffe Parkway culvert. EC5 from west of the main creek). The Active Channel is heavily forested with secondary side tributary is heavily forested and Both the Eastern and Western creek had growth deciduous forest. The flow was virtually dry during baseflow an active channel width ranging from 0.5 regime can be characterized as having periods. The channel cross-section is to 2.0 m with the Western Creek gradually shallow water depth and low flow wide and ill defined. increasing from upstream to downstream, velocity at the time of the assessment while the Eastern creek channel width · EC2: The channel morphology site (baseflow conditions) however the varied along its course. Maximum bank length was 44 m. This site was heavily channel planform is highly height ranged from approximately 450 mm forested with low banks. Overall EC2 straightened and the channel cross- to 700 mm in the Western creek and 350 does not demonstrate current signs section is in adjustment to the flows mm to 750 mm in the Eastern creek. from the Rockcliffe Parkway culvert. of erosion or instability. Exposed soils and stream bank

74 Aquafor Beech Ltd. August 2015 – Final Report EC3 EC1 consulting engineers 2150 THURSTON DRIVE, SUITE 203 OTTAWA, ONTARIO, K1G 5T9 TEL (613) 748-1415 FAX (613) 748-1356 www.dstgroup.com EC2 LEGEND:

EC4 CREEK LOCATIONS EC5

OSAP SURVEY LOCATION

SITE BOUNDARY

WC1

WC2

WC3

NOTE: 1. THIS DRAWING SHALL BE READ IN CONJUNCTION WITH THE ASSOCIATED TECHNICAL REPORT. 2. SOURCE - GOOGLE EARTH WC4

WC5 0 09/08/13 FINAL A.M. REV DATE ISSUE APPROVAL

PROJECT TITLE

AQUATIC HABITAT ASSESSMENT: WESTERN AND EASTERN CREEKS, FORMER CFB ROCKCLIFFE

DRAWING TITLE

SITE PLAN

DESIGNED BY SCALE A.M. N.T.S DRAWN BY DATE R.P. August 2013 PROJECT MANAGER PROJECT NO.: A.M. OE-OT-017184 FIGURE No.: FIGURE 2

Bank Angle creek ranged from 0 to 46 mm. In both found to have low to moderate levels of Overall, bank angles for both creeks range creeks the main channels were hydrated bank vegetative cover throughout its from 13° to 26°. The Western creek is along their entire length suggesting that length. Whereas, the Eastern Creek is characterized by higher bank angles these creeks are primarily groundwater characterized as having low to moderate (steeper banks) in the middle reaches as fed during baseflow conditions. This is levels of bank vegetation, it does display compared to the upstream and supported by the hydrogeological studies consistently high counts of instream cover downstream extents, while the Eastern (DST, June 2014). Overall, during baseflow (20 cover points/site), an important Creek displays shallower bank angles in conditions, both creeks can be component of aquatic habitat for fish the middle reaches and lower reaches. characterized as having shallow flow species. Cover is more varied in the depths and low flow velocities. Western creek with higher levels of instream cover observed at upstream Water Depth and Flow Bank Vegetation and Instream Cover locations as compared downstream. The water depth during baseflow In general, Western creek had more bank conditions in the Western creek ranged vegetative cover on average than the from 52 to 105 mm while the Eastern Eastern creek. The Eastern creek was

Table 19: Aquatic Habitat Assessment Findings- Channel Characteristics

L/R L/R Active Water Channel Hydraulic Max. Particle Instream Channel Bank Angles Site Channel Depth Depth Head (mm) (mm) Cover Points Slope (Degrees) width (m) (mm) (mm) WC5 0.55 52 458/466 0.59 28.32 33 0.27 16.88/16.47 WC4 1.31 88 648/691 0.36 13.14 14 0.45 22.64/24.15 WC3 1.02 105 693/572 1.36 49.09 34 0.38 24.56/20.71 WC2 1.54 61 703/686 2.05 98.50 51 0.46 24.89/24.30 WC1 1.77 76 485/531 1.14 114.75 30 0.34 17.54/19.21

EC5 1.84 30 732/756 0.17 72.00 21 0.49 25.74/26.40 EC4 0.52 26 465/524 0.45 106.40 20 0.35 17.05/18.97 EC3 1.82 0 447/474 0.0 19.26 24 0.29 16.53/17.42 EC2 0.98 25 357/353 0.16 2.09 18 0.22 13.26/13.09 EC1 1.95 46 525/575 0.05 55.56 19 0.38 18.99/20.85

76 Aquafor Beech Ltd. August 2015 – Final Report Bank Undercuts Water Temperature Macroinvertebrates Bank undercutting indicates locations Maximum summer water temperature was The 2013 assessment by DST also where active or historic bank erosion is or assessed by DST on July 24, 2013. considered the stream-bottom has occurred and is an indication of macroinvertebrate community, as these channel stability, state of adjustment, and Water temperature in the Western creek animals are an important link in the overall flow regime. was highest at the upstream but was aquatic food chain. considerably cooler in the deeper mid- In general, the Western Creek displayed reach sections of the creek (Table 21). The community of macroinvertebrates was few sever bank undercuts (Table 20), Lower mid-reach temperatures are likely found to be moderately diverse, ranging whereas the majority of the Eastern Creek influenced by a combination of factors from 9 to 15 taxa at each site, however displayed undercutting of the right bank. including temperature moderation from key indicator species were mostly absent. Other signs of erosion within the Eastern subsurface stormwater discharges, water The findings suggest that the overall Creek including slumping banks were also depth and heavy shade. habitat quality of the creeks varies from noted. Overall, it appears that moderate moderately good to moderately poor. levels of erosion are occurring along the In general, water temperature in the Most of the taxa found during the 2013 majority of the channel length of the Eastern Creek was highest at the surveys were relatively common taxa Eastern creek. Conversely, only a few downstream extent as compared to the which are either very tolerant or areas of moderate erosion within the upstream. Higher downstream water moderately tolerant to poor water quality Western creek were identified. temperatures are likely a result of and contamination. prolonged exposure to ambient air Table 20: Total Bank Undercuts temperature due shallow gradients and The limited number of macroinvertebrate Right Bank Site Left Bank (mm) the lack of an outlet to the at (mm) indicator species suggests that the best the raised pedestrian walkway. WC5 0 0 quality sites are WC5 and WC4 on the WC4 0 398 Western Creek and EC4 and EC3 on the WC3 150 80 Table 21: Water Temperature Water Temp. Air Temp. Eastern Creek. WC2 0 40 Site WC1 0 0 (°C) (°C) * WC5 17.5 EC5 10 1320 WC3 12.5 19.6-20.7 EC4 150 480 EC5 17.0 EC3 0 270 EC1 21.8 EC2 0 200 * http://climate.weather.gc.ca (accessed EC1 0 0 7/14)

Aquafor Beech Ltd. August 2015 – Final Report 77 F ish and Fish Habitat throughout its length, even during context of proposed connections and baseflow conditions. Water levels were habitat creation activities. Western Creek low throughout the Eastern Creek during Sites in the Western Creek appear to baseflow conditions and few deeper pools Aquatic Species at Risk (SAR) provide marginal fish habitat that could be were present to support fish. Per the Preliminary Terrestrial Habitat suitable for some common fish species, Assessment for the Proposed Stormwater however no fish were encountered during The Eastern Creek generally had low levels Ponds at the Former CFB Rockcliffe (DST, the fish surveys. While adequate instream of in-stream cover, most of which was 2013) included in Appendix E the Ontario cover exists in the Western Creek woody debris and virtually no aquatic Stream Assessment Protocol (OSAP) (particularly in its lower sections), most of vegetation throughout its length. The performed as part of the Aquatic Habitat the cover is woody debris, flat rocks, or banks were moderately to sparsely Assessment – Western and Eastern Creeks detritus, while very little aquatic vegetated, though the entire creek north (DST, 2013) has provided sufficient vegetation was observed. In its upper of the Rockcliffe Parkway was well-shaded information on the quality and character reaches the banks are well vegetated, by forest cover. of the aquatic habitat in these areas to while the downstream sites have relatively rule out the possibility that any aquatic less bank vegetation but are well shaded The Eastern Creek could potentially species at risk may be present in the by tree cover. While specific sites may be provide habitat for species that are survey area (DST, 2013). The OSAP suitable to support a low diversity fish tolerant of low water levels (sticklebacks assessment indicated that the creeks did community, it appears that the lack of for example), though no fish were found not support fish at the time of the survey, connectivity to the Ottawa River (as the during fish surveys. This is likely due to the nor do they support any rare or SAR final 550m of the creek runs subsurface) fact that there was no downstream varieties of invertebrates. Due to the poor and extensive entombment of creek connection to the Ottawa River at the quality of aquatic habitat and absence of sections have prevented fish from elevated recreational path and no significant open water, it is highly unlikely reaching potentially suitable sites. upstream connection to other habitats. that any wetland associated SAR birds, reptiles, insects, or fish would be present Eastern Creek It is likely that future connections to the within the survey area. During baseflow conditions, the main Ottawa River will likely result in an creek had very little water depth and its increase in fish species using the Eastern Stormwater Impacts on Aquatic Habitat side tributaries were found to be Creek as habitat. Future efforts in this With respect to aquatic habitat, the completely dry. However, the main body regard should evaluate species primary concern that has been identified of the creek maintained some flow composition in the Ottawa River in the with the proposed development and the

78 Aquafor Beech Ltd. August 2015 – Final Report associated stormwater management is the potential impacts related to changes in water temperature and increases in stream erosion. Erosion was discussed in Section 3.6, while temperature concerns are described below.

The DST Aquatic Habitat Assessment – Western and Eastern Creeks (2013) report concluded that the results of this aquatic habitat assessment indicate that there currently is little to no fish life in the creeks, nor are there many sensitive varieties of macroinvertebrates. The habitat can generally be considered low quality and there are only small isolated patched of aquatic vegetation present. Hence there are few biotic values present within the creeks themselves which would be sensitive to water temperature changes. Because neither creek has large flow volumes nor high flow velocity, any temperature changes resulting from the stormwater management plan will return to ambient conditions long before reaching the Ottawa River and hence no thermal impacts on the river are expected. Therefore, temperature mitigation measures should not be required for the outflows from the stormwater facilities.

Aquafor Beech Ltd. August 2015 – Final Report 79 3. 8 TERRESTRIAL ECOLOGY updated in 2013 to account for changes groupings on the site, and identifies their impacting the site. These include changes condition. Companion existing conditions reports for in legislation, changes to tree health, and Provincially Designated Natural Areas the Rockcliffe lands provides a changes to development on the site. comprehensive summary of the existing There are four provincially designated Vegetation on the Former CFB Rockcliffe vegetation communities including natural areas within one kilometer of the CDP site is generally consistent with Provincially Designated Natural Areas and site; however the only area with the vegetation found in the greater Ottawa Urban Natural Areas, as well as list of potential to be impacted by the area, which is part of the Great Significant Vegetation and Wildlife redevelopment of the site is the Rockcliffe Lakes/Saint Lawrence Forest region. This Species. A detailed report entitled CFB Airbase Woods. These woods are located forest region is represented by a mixture Rockcliffe Vegetation Survey (Baker, northeast of the Rockcliffe Parkway and of deciduous and coniferous trees. January 2013) is included in Appendix G. Airport-Marina Road and are characterized by a rolling landscape of deep marine clay The following discussion is limited to the On site native tree species identified that is lightly and irregularly covered by context of stormwater management as include Sugar Maple, Basswood, Red Oak, sand and silty sand and dominated by a part of the landscape level system for the White Pine, White Spruce, and White young to submature upland deciduous maximization of the function of Cedar as well as Bitternut Hickory, forest. The underlayer of impervious clay vegetation, ensuring the protection of the Butternut, and Silver Maple. has created complex moisture conditions natural hydrologic function and linkages Non-native tree species identified on site, across the site, resulting in equally between surface and groundwater sources including Black Locust, Norway Maple, complex variations in forest dominants. and vegetation, wildlife and natural Norway Spruce, Blue Spruce, and Weeping This site supports the largest clay-based heritage features through groundwater Willow. upland area of relatively natural recharge, temperature moderation vegetation in Ottawa (NHIC, 2013). strategies and the creation of wildlife In general, the trees recommended for habitat. retention on the site are native trees, as Urban Natural Areas Vegetation some non-native species tend to be The prepares reports on invasive (i.e., Norway Maple). However, Urban Natural Areas (UNAs) within the As part of this project, the inventory of some non-native trees are recommended City, detailing the fauna and flora, and the trees and tree groupings on the site for retention on the site. Figure 21 general health of the area. Within the prepared in 2004 was reviewed and provides a survey of existing trees and tree

80 Aquafor Beech Ltd. August 2015 – Final Report vicinity of the former CFB Rockcliffe site, within and off-site of the Former CFB identified shallow groundwater system there are five UNAs (Figure 22): Rockcliffe CDP site and that all SWM (shall potentiometric contours) illustrated proposed controls be designed as passive on Figure 10, stormwater practices, 1. the Airbase Woods, stormwater management systems that specifically infiltration based controls, on maintain the hydrologic connection of the Former CFB site will affect the 2. the NRC Woods North, both surface and groundwater to the hydrologic function of downstream UNAs, 3. the Montfort Hospital Woods, identified communities. In this regard, specifically (Figure 22): special consideration should be given to: 4. the Carson Grove Woods, and 1. the Airbase Woods, · The maintenance of the existing 5. the Assaly Woods. hydrologic regime, specifically the 2. the NRC Woods North, enhancement of groundwater It is unlikely that stormwater on-site From an ecological standpoint, the two recharge, of the three (3) significant controls will affect the hydrologic regime most valuable vegetated areas in the on-site vegetation communities and groundwater systems contributing to vicinity of the site are the Montfort (Figure 21): the upstream UNAs, specifically: Hospital Woods and the NRC Woods North. The Montfort Hospital woods are 1. North of Dubhe Private at the 1. the Montfort Hospital Woods, owned by the National Capital headwaters of the Western Creek Commission. The City of Ottawa has 2. the Carson Grove Woods, and confirmed that any development within 30 2. North of Hemlock Private on both m of these features will require the sides of Hurley Crescent 3. the Assaly Woods. completion of an Environmental Impact

Statement (EIS). 3. North of Arcturus Private, east of Vegetation and Stormwater Management Burma Road.

It is recommended, that as part of a The maintenance of the existing landscape level stormwater management hydrologic regime, specifically the system that all SWM techniques maintain enhancement of groundwater recharge, as and enhance the form and function of it relates to the adjacent (off-site) Urban existing vegetation communities both Natural Areas (UNAs). Based on the

Aquafor Beech Ltd. August 2015 – Final Report 81

1

2

3

Figure 21: Inventory of Existing Trees and Tree Groupings in the Study Area

82 Aquafor Beech Ltd. August 2015 – Final Report Figure 22: Urban Natural Areas

Aquafor Beech Ltd. August 2015 – Final Report 83 Terrestrial Habitat

A report entitled Preliminary Terrestrial Habitat Assessment for Proposed Stormwater Ponds at the Former CFB Rockcliffe was prepared by DST (August 2013) and is summarized below. Source materials and reports are included in Appendix E.

The purpose of the preliminary terrestrial habitat assessment was to briefly characterize the habitat that occurs on adjacent parcels of National Capital Commission (NCC) land north of the Former CFB Rockcliffe CDP site and to conduct a high level screening of the Ontario Ministry of Natural Resources (OMNR) online information on Species at Risk (SAR) to determine which SAR may be present on site, based on the presence of Figure 23: Preliminary Terrestrial Habitat Assessment – Study Area (DST, 2013) potentially suitable habitat. The surveyed Rockcliffe Parkway (the Eastern SWM south. The boundary between the NCC area is illustrated on Figure 23. Note: at Facility). parcel south of the Rockcliffe Parkway and the time of the assessment, two the former CFB Rockcliffe property is a cliff stormwater management ponds were The terrestrial habitat in the area of the which varies between vertical rockface proposed in the vicinity of these areas. proposed location of the Eastern SWM and sections of steep rocky slopes along Currently only one (1) stormwater Facility can be characterised as grassland the southern edge of the survey area. management pond is proposed within the immediately south of the Rockcliffe subject area immediately upstream of the Parkway, with thick secondary growth Based on the habitat features noted, the Eastern Creek on the south side of the deciduous forest growing around the base proposed locations of the stormwater of the cliffs and cliff slope further to the management pond has the potential to be

84 Aquafor Beech Ltd. August 2015 – Final Report Table 22: Possible SAR Based on Presence of Potentially Suitable Habitat (Source: DST, 2013) suitable habitat for SAR associated with grasslands, deciduous forest, and cliff environments.

Terrestrial Species at Risk (SAR) Based on the presence of grassland, secondary growth deciduous forest, and cliff habitats, potentially suitable habitat exists in the survey area for the SAR listed below in Table 22. Aquatic associated SAR have been excluded from the list presented in Table 22 are discussed in Section 3.7 – Aquatic Species at Risk (SAR).

It should be noted that Butternut tree (Juglans cinerea) survey was completed by DST in July 2013 for the same study area (Figure 23) and is discussed separately in subsequent section. With the exception of Butternut trees, the actual presence/absence of SAR in the survey area has not yet been confirmed and there are currently no known occurrences of SAR in the survey area.

Aquafor Beech Ltd. August 2015 – Final Report 85 T he Species at Risk Survey included · Butternut trees were identified at the · The Preliminary Terrestrial Habitat consultation with the Ontario Ministry of CLC property, north of the property, as Assessment identified the potential Natural Resources; review of the well as along the Eastern Creek. The that exposed rock crevices and rock Committee on the Status of Endangered Butternuts are classified as Category 1 cracks within the cliffs/exposed Wildlife in Canada (COSEWIC) and the (non-retainable, for example, bedrock areas could serve as bat Species at Risk Ontario (SARO) SAR status terminally infected with Butternut maternity roosting or hibernation reports and range maps for the target Canker) or Category 2 (considered habitats. The escarpment beyond the species; review of the Natural Heritage retainable). Most of these trees were northern CLC property boundary is Information Center (NHIC) mapping and clustered within the forest patch characterized by a steep drop in historical records of SAR occurrences. In growing along the edge of the topography moving from south to addition, the scope of work included escarpment. Additional detail is north, with areas of exposed rock, identification of species-specific mitigation provided in subsequent sections. rock crevices, and rock cracks creating measures and discussion of anticipated unusual geologic conditions. Such SAR related permitting requirements. · The Monarch Butterflies were noted at features have the potential to serve as Mitigation and permitting information three locations within fields containing either summer roosting habitat and/or presented in this report should be Milkweed plants within the survey hibernation sites for some bat species. reviewed and confirmed in the context of area. Due to the presence of Milkweed Three SAR bat species (Little Brown the more detailed impact assessments plants, it is presumed that Monarch Myotis, Northern Myotis, and that will be undertaken as part of the Butterfly are both foraging and Tricolored Bat) were found to occur forthcoming Environmental Impact breeding within the survey area. within the survey area. A Statement (EIS) and Environmental Effects comparatively small number of Analysis (EEA) studies. · Common Nighthawk were heard recordings were documented for each calling. It is presumed that Common of these species, suggesting that while Based on the above-noted records review, Nighthawk may utilize the survey area these species are present within the DST compiled a list of 24 SAR which may for foraging purposes but no evidence survey area, it is unlikely that a large potentially be present within the survey of nesting behavior within the survey colony exists for any of the SAR bats. area. Survey results indicate the presence area was noted (calls were heard The number of recordings observed of six species, as follows: outside the survey area) and for each species is similar to therefore, no significant habitat background levels of activity observed features were noted for this species. by DST for the SAR bats throughout

86 Aquafor Beech Ltd. August 2015 – Final Report the Ottawa area, and suggests that Species at Risk Survey report. The these species are utilizing the survey Due to the presence of potentially forthcoming EIS/EEA should elaborate on area and adjacent grasslands, significant bat roosting habitat, which these mitigation measures to address meadows, and forested areas adjacent may serve as a summer roosting sites other environmental impacts that are not to the Rockcliffe and Aviation for small numbers of SAR bats and for specific to these species, as the list of Parkways for foraging purposes only. It larger numbers of Big Brown Bats, DST mitigation measures outlined in the is also possible that small numbers of recommends that the future EIS/EEA Species at Risk Survey report are not the SAR bats utilize rock crevices and should evaluate potential impacts to intended to address all potential cracks within the Rockcliffe this feature. The Rockcliffe environmental concerns. Ultimately, the Escarpment as summer roosting sites. Escarpment is contained wholly within EIS/EEA should include mitigation Because all three SAR bats typically the NCC lands, and hence would be measures related to environmental hibernate communally in sites with within federal jurisdiction. It should be impacts from the proposed undertaking. constant temperature conditions (e.g. noted that none of the SAR bats are caves, abandoned mines, large currently listed under Schedule 1 of Butternut Survey tunnels, etc.) and no large openings or SARA, and hence do not require SARA- A report entitled Butternut Survey for caves have been noted within the related permitting. Ontario Ministry of Proposed Stormwater Ponds at the Former escarpment, it is unlikely that the SAR Natural Resources (OMNR) guidance CFB Rockcliffe was prepared by DST bats would overwinter within the dictates that bat hibernacula and (August 2013) and is summarized below. escarpment. There was not an roosting sites should be protected by a Source materials and reports are included observed significant increase in the buffer of 120 m and that impacts to in Appendix F. number of recordings for the SAR bat the habitat within 120 m of the species over the course of the survey, feature should be considered as part The Butternut was declared a nationally and no evidence of swarming activity of an EIS/EEA (OMNR 2011). endangered species by the Committee on within the survey area for these Mitigation measures include pre- the Status of Endangered Wildlife in species was observed. Migratory Silver construction searches of any affected Canada (COSEWIC) in November of 2003. Haired Bats (not an SAR) increased in areas of the escarpment and a work This species is listed as endangered, both abundance towards the end of August, timing window. federally under the Species at Risk Act and suggesting that this species is provincially under the Ontario Endangered migrating through the survey area at Several mitigation measures specific to the Species Act. Butternut is primarily at risk that time. SAR identified have been outlined in the due to the effects of a fungal pathogen

Aquafor Beech Ltd. August 2015 – Final Report 87 ( Sirococcus clavigignenti-juglandacearum) Management Options which causes wounds known as Butternut Butternut trees identified at the CLC Cankers. Butternut Cankers are property, north of the property, as well as responsible for the loss of approximately along the Eastern Creek are classified as one third of the Butternut population. It is possible for a tree to live · Category 1 (non-retainable, for many years with the Canker, although example, terminally infected with most only live a few years after infection Butternut Canker) or (OMNR 2013). In Canada, Butternut can be found in Quebec, New Brunswick, and · Category 2 (considered areas in Ontario (southwestern to south of retainable). Most of these trees the Canadian Shield) (OMNR 2013). This were clustered within the forest species does well in moist, well-drained patch growing along the edge of soils, preferring to grow in small clearings the escarpment. Additional detail within a forest, or at the forest edge is provided in subsequent (OMNR 2013). sections. Category 2 Butternut trees are illustrated on Figure 24. All living trees within the survey area were examined, the presence/absence of Butternut noted and identified to the genus, and any members of a genus which are superficially similar to Butternut were identified to species level.

Twenty eight (28) Butternut trees were found within the survey area, most of these trees were clustered within the forest patch growing along the edge of the cliff.

88 Aquafor Beech Ltd. August 2015 – Final Report

Figure 24: Butternut Location Plan (Source: DST, 2014) Aquafor Beech Ltd. August 2015 – Final Report 89 3.9 SUMMARY OF The native overburden comprises clay to bedrock groundwater surface across most EXISTING CONDITIONS silt marine deposits over the Southern half of the property, with the exception of the of the study area, silty to sandy till plain in top of the escarpment located in the The following represents key findings parts of the Western and Northern northwest corner of the site. From the concerning existing conditions within the portions, and sand/silt alluvial sediments 2014 data analyzed by Aquafor Beech for Former CFB Rockcliffe CDP site (study forming parts of the Western portion of 14 monitoring wells, the range of water area). The findings are discussed in light of the study area. levels was between 0.18 and 2.09 m. the comprehensive review of recent Data on hydraulic conductivity (from rising background assessments and In summary, the generalized stratigraphy or falling head slug tests) show that: investigations discussed in detail earlier in for the east side of the site consists of asphalt surface treatment underlain by the Chapter. · Sand and sandy gravel has K values granular sand and gravel which is again between 10-6 and 10-7 (m/sec) Geology and Hydrogeology underlain by silt or clay layer followed by · Silty clay and clay till have K values bedrock. The generalized stratigraphy for between 10-6 and 10-8 (m/sec) The study area includes two connected the west side of the site consists of a thin · Limestone bedrock has K values hydrogeological units in the area: the layer of topsoil underlain by silty clay and between 10-8 and 10-9 (m/sec) overburden unit and the shallow bedrock sand and gravel layers followed by unit. There are variable thicknesses and possible bedrock. types of overburden materials overlying In-situ hydraulic conductivity testing, the bedrock: The elevation across the study area ranges found that the field saturated hydraulic from about 70 to 90 m above sea level conductivity varies across the site per the · Areas with shallow overburden soil (asl). The base of the escarpment various soil types and that localized areas (less than 2 m of overburden thickness descends to approximately 55 m asl at the of high infiltration encountered (more overlying bedrock) covering Rockcliffe Parkway, and about 45 m asl at than 490mm/hr) and generally correspond approximately 17% of the study area; the Ottawa River. to localized areas of sandy soil. In and addition, localized areas of low infiltration Groundwater on site flows from north to encountered (less than 1 mm/hr) and · Areas with overburden thickness northwest, approximately following the generally correspond to silty clay soils. ranging from greater than 2 m to local topography descending towards the Silty clay and clay till generally found to be about 10 m. Ottawa River. In general, the overburden lower in original estimates as compared to water table is slightly higher than the in-situ testing. Using all available data and

90 Aquafor Beech Ltd. August 2015 – Final Report employing a sensitivity analysis, an Existing Drainage series of culverts, roadside ditches, and/or average hydraulic conductivity was natural watercourses. determined to be 9.5mm/hr and Drainage features within the study area Hydraulics 5.2mm/hr for the Western and Eastern include a major drainage system and a minor drainage system. The major Creek Subwatersheds respectively. The flow discharge from the study area is drainage system includes two currently conveyed to two existing culvert watercourses (creeks) that drain major Surface Water Features crossings at the Aviation and Rockcliffe storm events and outlet to the Ottawa Parkways. There are three watercourses flowing River. The Western Creek bisects the site within and around the Former CFB and originates at the southeast corner (on The first crossing at the Aviation Parkway Rockcliffe site: National Research Council lands), and on the west edge of the Former CFB discharges at the northwest edge of the Rockcliffe CDP site (West Outlet) consists of a 0.91m diameter (36”) CSP. The 1. Western Creek site, crossing the Aviation Parkway via a following information has been compiled 2. Eastern Creek culvert and outletting to the Ottawa River. from field survey work. The upstream and 3. Northeastern Escarpment The Eastern Creek provides drainage to downstream inverts were surveyed at Tributary to the Eastern Creek the northeast quadrant of the site and elevations 60.25m, and 60.16m, drains runoff northward over the north respectively. The culvert is approximately The Eastern and Western creeks have escarpment, ultimately discharging to the 137m in length with slope of 0.07%. tributaries that originate within the Ottawa River. Results indicate that the peak capacity of Former CFB Rockcliffe CDP site, and both the existing culvert is approximately 0.85cms, with water surface elevation at also merge with tributaries flowing from In regard to the minor drainage system, a 61.75m at the upstream end of the adjacent properties. The Northeastern combined sewer system is present on the culvert. Escarpment Tributary originates from an site, in addition to two storm sewer existing storm sewer outlet. systems: one collects surface runoff from Rockcliffe Parkway at the eastern edge of the central portion of the site (near Via the Former CFB Rockcliffe CDP site (East These creeks flow into the Ottawa River Venue and Codd’s Road) and the second Outlet) is comprised of a 1.24m diameter and have sections which flow through carries runoff from the Thorncliffe Park (48”) CSP. The following information has underground stormwater piping and residential development (immediately been compiled from field survey work. culverts. south of the site). Both systems eventually The upstream and downstream inverts discharge into the Ottawa River through a were surveyed at elevations 52.52m and

Aquafor Beech Ltd. August 2015 – Final Report 91 5 2.15m, respectively. The culvert is Hydrology Water Budget approximately 28m in length with slope of In support of the proposed development Water Budget Analysis is required to 1.3%. The results indicate that the peak within the Former CFB Rockcliffe CDP site, understand the overall hydrology of the capacity of the existing culvert is IBI Group has completed a preliminary study area, and evaluate the relationship approximately 3.5cms, with water surface hydrological analysis of the existing site between precipitation and the response of elevation of 54.80m at the upstream end conditions, and conceptual stormwater the study area to precipitation events over of the culvert. As discussed in previous management for the proposed a long timeframe. The overarching development. objective of understanding the water sections, no outlet to the Ottawa River budget is so that one can analyze the currently exists for the Eastern Creek. The hydrologic analysis of the study area existing conditions hydrology in order to was conducted using SWMHYMO establish baseline conditions, which will be From the hydraulic analysis, the existing computer model. According to the IBI outlets from the system are constrained used later to carry out an impact documentation, the modeling effort assessment of future development and by capacity limitations at the Eastern included the analyses of existing outlet and Western outlet at the Rockcliffe develop stormwater management targets. conditions, future conditions, and future There are many benefits that result from a and Aviation Parkways respectively. conditions with two SWM facilities (i.e. Therefore, assuming a suitable outlet for water balance assessment. These benefits Eastern SWMF and Western SWMF). include: the Eastern Creek can be constructed at the Ottawa River, from a hydraulics Existing Conditions · Identifying key elements in the perspective any future stormwater Peak Flow Peak Flow Hydrological Cycle, including management system must either: to Western to Eastern Design Storm surface runoff, Outlet Outlet evapotranspiration, and a) Control post-development flows to (cms) (cms) infiltration; respect the capacity of the existing 2 Year, 24 Hr, 3.91 2.97 infrastructure SCS Type II · Defining streamflow regime and 5 Year, 24 Hr, 5.76 4.37 variability; and b) Provide sufficient capacity to convey SCS Type II · Providing baseline conditions to post-development flows such that 100 Year, 24 11.56 8.83 help develop stormwater major flows can be safely conveyed to Hr, SCS Type II management targets. the Ottawa River (where flood control is not required). From the analysis, the existing conditions water budget was determined and is presented below.

92 Aquafor Beech Ltd. August 2015 – Final Report Water Budget Analysis Results for the base material. It is assumed that the flow velocity and bed shear stress Study Area channel was disturbed by flow from the will not be affected Water Budget Volume existing culvert, leading to the b. Eastern - estimated bankfull Component (mm/year) destabilization of the downstream discharge is 1500 l/s. Total Precipitation 887 channel. 2. Implemented stormwater pond design Surface Runoff 120 Unlike the Western Creek, the Eastern should not change the input discharge Creek has several sub-reaches that show Evapotranspiration 532 or sediment load to either creek. signs of channel instability, including Infiltration 235 exposed roots on channel banks and over- In addition, it is noted that enhancement to sized channel dimensions. The most the western Creek are required to remove upstream reach appears to be the most debris between Havelock Rd and the Fluvial Geomorphology destabilized, which is likely attributable to Aviation Parkway (removal of silt build up in For the purpose of characterizing the the culvert under the Rockcliffe Parkway the creek at the outlet of the Aviation fluvial geomorphology of the Eastern and and resultant potential augmentation Parkway culvert), and remove the blockage Western Creek systems under existing and/or grade change. in a culvert within the RCMP campus is conditions, the Fluvial Geomorphology required to restore a positive outlet. Assessment Study prepared by DST In both creeks, it was observed that (September, 2013) was reviewed. engineering works such as culverts have Aquatic Ecology the potential to destabilize the channel. The Western Creek was determined to be An aquatic habitat assessment was geomorphically stable, with most reaches The recommendations of the Fluvial undertaken for the Western Creek and lacking obvious signs of ongoing erosion. Geomorphology Assessment Study Eastern Creek downstream from the However, sub-reaches between Hemlock included the following: Former CFB Rockcliffe CDP site in order to Road and the Aviation Parkway did show assess potential impacts on aquatic signs of instability, and a reach 1. It is imperative that any future habitat resulting from the management of immediately downstream of a culvert stormwater detention pond designs stormwater for the site. north of the Aviation Parkway was minimize perturbation of the channel. deemed to be an eroding steep-walled a. Western – Report authors suggest The assessment was undertaken using the gully with a very steep (5%) channel bed 800 l/s will have no significant Ontario Stream Assessment Protocol and incising into the consolidated clay impact to the creek stability as the (OSAP) (Stanfield 2010), and it included

Aquafor Beech Ltd. August 2015 – Final Report 93 e xamining five (5) reaches of both the moderate levels of bank vegetation, it temperature due to the lack of outlet Western Creek and Eastern Creek. Key does display consistently high counts to the Ottawa River at the raised findings included: of instream cover (20 cover pedestrian walkway. points/site), an important component · Active Channel: Both the Eastern and of aquatic habitat for fish species. · Macroinvertebrates: The community Western creek had an active channel Cover is more varied in the Western of macroinvertebrates was found to width ranging from 0.5 to 2.0 m. creek with higher levels of instream be moderately diverse, ranging from Maximum bank height ranged from cover observed at upstream locations 9 to 15 taxa at each site, however key approximately 450 mm to 700 mm in as compared downstream. indicator species were mostly absent. the Western creek and 350 mm to 750 mm in the Eastern creek. · Bank Undercuts: In general, the · Fish and Fish Habitat: Sites in the Western Creek displayed few sever Western Creek appear to provide · Bank Angle: Overall, bank angles for bank undercuts, whereas the majority marginal fish habitat that could be both creeks range from 13° to 26°. of the Eastern Creek displayed suitable for some common fish undercutting of the right bank. Other species, however no fish were · Water Depth and Flow: The water signs of erosion within the Eastern encountered during the fish surveys. depth during baseflow conditions in Creek including slumping banks were It appears that the lack of the Western creek ranged from 52 to also noted. connectivity to the Ottawa River (as 105 mm while the eastern creek the final 550m of the creek runs ranged from 0 to 46 mm. during · Water Temperature: Water subsurface) and extensive baseflow conditions, both creeks can temperature in the Western creek entombment of creek sections have be characterized as having shallow was highest at the upstream but was prevented fish from reaching flow depths and low flow velocities. considerably cooler in the deeper potentially suitable sites. The Eastern mid-reach sections of the creek. In Creek could potentially provide · Bank Vegetation and Instream Cover: general, water temperature in the habitat for species that are tolerant The Eastern creek was found to have Eastern Creek was highest at the of low water levels (sticklebacks for low to moderate levels of bank downstream extent as compared to example), though no fish were found vegetative cover throughout its the upstream. Higher downstream during fish surveys. This is likely due length. Whereas, the Eastern Creek is water temperatures are likely a result to the fact that there was no characterized as having low to of prolonged exposure to ambient air downstream connection to the

94 Aquafor Beech Ltd. August 2015 – Final Report Ottawa River at the elevated Bitternut Hickory, Butternut, and Silver are the Montfort Hospital Woods and the recreational path and no upstream Maple. NRC Woods North. connection to other habitats. Non-native tree species identified on site, It is recommended, that as part of a Moreover, the OSAP assessment including Black Locust, Norway Maple, landscape level stormwater management indicated that the creeks did not Norway Spruce, Blue Spruce, and Weeping system that all SWM techniques maintain support any rare or SAR varieties of Willow. and enhance the form and function of invertebrates. Due to the poor quality existing vegetation communities both In general, the trees recommended for of aquatic habitat and absence of within and off-site of the Former CFB retention on the site are native trees, as significant open water, the report Rockcliffe CDP site including three (3) some non-native species tend to be noted that it is highly unlikely that significant on-site vegetation invasive (i.e., Norway Maple). However, any wetland associated SAR birds, communities: 1) North of Dubhe Private at some non-native trees are recommended reptiles, insects, or fish would be the headwaters of the Western Creek; 2) for retention on the site. present within the survey area. North of Hemlock Private on both sides of Hurley Crescent; and 3) North of Arcturus The DST Aquatic Habitat Assessment There are four provincially designated Private, east of Burma Road and two (2) report indicated that temperature natural areas within one kilometer of the UNAs downstream of shallow groundwater mitigation measures should not be site; however the only area with the system including: 1) the Airbase Woods; required for the outflows from the potential to be impacted by the and 2) the NRC Woods North. stormwater facilities proposed for redevelopment of the site is the Rockcliffe stormwater control within proposed areas. Airbase Woods. Terrestrial Habitat: The terrestrial habitat in the area of the proposed location of the Terrestrial Ecology Within the vicinity of the former CFB Eastern SWM Facility can be characterised Background documents revealed the Rockcliffe site, there are five (5) Urban as grassland immediately south of the following information: Natural Areas (UNAs); the Airbase Woods, Rockcliffe Parkway, with thick secondary the NRC Woods North, the Montfort growth deciduous forest growing around Vegetation: it was noted that on site Hospital Woods, the Carson Grove Woods, the base of the cliffs and cliff slope further native tree species identified include Sugar and the Assaly Woods. From an ecological to the south. The boundary between the Maple, Basswood, Red Oak, White Pine, standpoint, the two most valuable NCC parcel south of the Rockcliffe Parkway and the former CFB Rockcliffe property is a White Spruce, and White Cedar as well as vegetated areas in the vicinity of the site cliff which varies between vertical rockface and sections of steep rocky

Aquafor Beech Ltd. August 2015 – Final Report 95 s lopes along the southern edge of the survey area.

Terrestrial Species at Risk: The Species at Risk Survey included consultation with the Ontario Ministry of Natural Resources; review of the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) and the Species at Risk Ontario (SARO) SAR status reports and range maps for the target species; review of the Natural Heritage Information Center (NHIC) mapping and historical records of SAR occurrences. In addition, the scope of work included identification of species- specific mitigation measures and discussion of anticipated SAR related permitting requirements. Based on the above-noted records review, DST compiled a list of 24 SAR which may potentially be present within the survey area. Survey results indicate the presence of six species, as follows: Butternut; Monarch Butterfly, Common Nighthawk and three (3) bat species - Little Brown Myotis, Northern Myotis, and Tricolored Bat.

96 Aquafor Beech Ltd. August 2015 – Final Report

MSS STORMWATER STRATEGY

Aquafor Beech Ltd. February 2015 i 4. 1 INTRODUCTION The evaluation was carried out in In regards to stormwater management, conjunction with the CDP process, out of the Stage 1 evaluation identified a As detailed in the Master Servicing Study which a preferred development concept separate storm sewer system, complete (MSS) completed by IBI (2015), an plan and preferred municipal servicing with end-of-pipe SWM facility(ies) as integrated environmental assessment and plan are identified. The evaluation was preferred. The storm sewer system will be planning process has been completed and completed in sufficient detail to satisfy designed to current City of Ottawa and is detailed in Chapter 3 of the MSS. The Phases 1 and 2 of the MEA Municipal Class MOE design guidelines and in parallel with Municipal Class Environmental Assessment EA process and, as part of the CDP the LID Pilot/ Demonstration project. (EA) process recognizes the benefits of process, included consultation with review Stage II – Identification and Evaluation of integrating approvals under the agencies, stakeholders, and the public Environmental Assessment Act and the Stormwater Alternatives Finally, with the identification of a Planning Act. In support of the preferred servicing preferred concept plan and preferred technique established in the Stage I From the perspective of the MSS, the municipal servicing plan, design evaluation, three (3) municipal servicing problem presented by this proposed parameters are developed for water, alternatives have been developed for each redevelopment of the Former CFB wastewater and stormwater to facilitate municipal service (water, wastewater and Rockcliffe site and the associated increase more detailed design work for each stormwater). in density is the provision of municipal municipal service. services to adequately service the In regards to stormwater management, Stage I – Identification and Evaluation of preferred concept plan, and to incorporate the, Alternative III was identified as the Stormwater Solutions these services into the existing preferred alternative for stormwater. This surrounding municipal infrastructure while Based on the Stage 1 evaluation of alternative includes two end-of-pipe SWM meeting the design criteria and level of servicing solutions, the expansion of the facilities to balance stormwater discharge service requirements of the City of Ottawa existing municipal infrastructure system between the existing outlets recognizing and other regulatory agencies. was determined to be the best servicing the constraints and opportunities technique to advance. The technique will associated with these outlets, minimize To assist in developing a preferred service the former CFB Rockcliffe site storm pipe sizes and depth, and to servicing solution for the redevelopment while minimizing negative impacts to the facilitate construction phasing. of Former CFB Rockcliffe, a two stage social and natural environment. evaluation process was utilized.

98 Aquafor Beech Ltd. August 2015 – Final Report The details of the preferred alternative good opportunity to control major flow The construction of the Eastern SWM from the MSS (IBI, 2015) for stormwater along the corridor, if necessary. The Facility may require upgrades to the management (Alternative III) are proximity of the collector road to the existing outlet channel and/or the summarized in regards to the evaluation proposed trunk storm servicing corridor construction of a new storm sewer outlet criteria of Serviceability, Social, Natural also provides the opportunity to increase from the SWM facility to the Ottawa River Environment and Cost. discharge to the storm trunk system with due to the restricted space available at minimal impact to the local storm system, this location and potential design Serviceability if necessary. Due to the sewers primarily constraints imposed by the NCC. in proposed rights-of-way, and off-site To service the Former CFB Rockcliffe site, SWM facilities that are significantly Natural Environment two major SWM facilities have been downgradient of the development, the proposed to direct runoff from the site to Existing combined sewer system to be design is expected to have minimal impact both Western and Eastern Creeks. These eliminated and replaced by separate on the aesthetics or functionality of the two facility systems, and the existing sanitary and storm sewers. Baseflow that development. topography, offers the opportunity to had previously been diverted to the balance the post-development flow This parallel study which is evaluating the combined system is now conveyed to the between the two creeks, mitigating the potential to add LID technique to the natural environment. Since a SWM facility constraints associated with each creek. storm system may result in further is proposed at the headwaters of both Majority of the trunk storm sewers are in enhancement of the development’s creeks, baseflow to both creeks will be proposed rights-of-way, servicing aesthetics and the functionality of the enhanced, and there is the potential to associated frontage, resulting in an storm system. improve aquatic habitat of both creeks. efficient design from an overall sewer length perspective. Size and depth of the Social Existing topography of the site also trunk storm sewers is also minimized, provides opportunity to balance the post- relative to the single SWM facility options, Construction of two SWM facilities, development flow between the two and also maximizes phasing potential. together with the site topography, offers outlets, minimizing impact on both creeks. the opportunity to balance post- However, physical constraints associated Location of the main collector road on the development flow. This would assist in with the western outlet suggest a limited preferred concept plan is such that there minimizing the required upgrades to the ability to convey post-development flow, are numerous locations where the green Western Creek, thereby lessening impact compared to the eastern outlet. Any space abuts the collector road, offering to the adjacent community. upgrades required to mitigate constraints

Aquafor Beech Ltd. August 2015 – Final Report 99 in the Eastern Creek will require tree Since most of the storm sewers are 1. Eastern SWM Facility removal and/or the construction of a located in proposed roads with useable storm sewer directly to the Ottawa River. frontage, the system is considered to be 2. Western SWM Facility relatively cost effective from a capital and Construction of the Eastern SWM Facility, Potential use of natural channel design long term operating and maintenance cost adjacent to the Rockcliffe Parkway, will techniques and a reforestation program perspective. can be implemented to minimize long include a new pipe conveying outflow term impact to natural environment. Any Figure 3.4 of the MSS (IBI, 2015), from the facility to the Ottawa River. Due work in the Eastern Creek has the added illustrates the preferred servicing solution to the direct connection to the Ottawa benefit of creating an outlet to the Ottawa for water, wastewater and stormwater River, it is not required the Eastern SWM River at the recreational pathway, which management. Figure 26 and Figure 27 Facility provide water quantity control. provides an opportunity to enhance the illustrate the final preferred servicing Additional field work and consultation creek’s aquatic habitat. It will also provide solution which evolved through agency with the NCC and RVCA will be required as opportunity to stabilize the creek slopes and municipal consultation and part of detailed design. and terminate the active erosion which is engineering design activities. The Western SWM Facility is tributary to currently occurring. Preferred SWM Alternative Regulatory the Aviation Parkway culvert crossing. Cost Requirements Enhancement to remove debris from the Aviation Parkway culvert, remove silt build A summary of the regulatory requirements Requires construction of two SWM up in the creek at the outlet of the of the preferred stormwater alternative facilities; however, the overall sewer Aviation Parkway culvert, and remove the from the MSS (IBI, 2015) are detailed system is relatively cost effective due to blockage in a culvert within the RCMP below in regards to Water Quantity, Water the reduced sewer sizes and sewer depths campus is required to restore a positive Quality, Erosion Control, Temperature, as a result of multiple outlets. outlet. Water Budget, and Level of Service (LOS) Additional costs associated with Water Quality Water Quantity constructing two SWM facilities would be significantly offset by the savings in sewer The two (2) SWM facilities servicing the As previously discussed, the preferred costs throughout the development. site will provide an Enhanced Level of SWM alternative is comprised of two end- Protection, which corresponds to 80% TSS of-pipe SWM facilities with outlets to the removal as per the Stormwater Ottawa River:

100 Aquafor Beech Ltd. August 2015 – Final Report Management Planning and Design Manual Water Budget ratio must be consistent with the (Ontario Ministry of the Environment, runoff coefficient. March 2003). The existing conditions water budget analysis as detailed in Section 3.2 of this · Designs of sewer systems in Erosion Control report was included within the MSS in Greenfield developments are not to order to provide baseline conditions from be completed on the basis of unit ICD Pre the MSS, it is recommended that the which targets could be developed. flow rates. ICD flow rates are to be future SWM facility designs minimize calculated for each drainage area to perturbation of the creek channels. The Level of Service (LOS) ensure that the stormwater Eastern Creek is characterized by eroding, management (SWM) objectives are The level of service for future incising reaches separated by depositional satisfied. wet grassy areas. The estimated bankfull development is to be based on the latest discharge is between 0.5 cms and 2.5 cms. City of Ottawa guidelines. The key · The maximum flow depth on streets recommendations of Technical Bulletin under either static or dynamic The Western Creek is generally stable 2012-4 are summarized as follows: conditions shall be 300 mm. Flow except upstream of the Aviation Parkway depth of runoff on street rights-of- · An inlet time of 10 minutes is to be (which is going to be modified by way is not to extend onto private used for all land uses and lot grading development). The estimated bankfull property. discharge is between 0.7 cms and 1.4 cms configurations. For the sizing of sewer downstream of the Aviation Parkway and segments (leads) connecting back · In addition to the use of Historical upstream of the confluence with the yard catchbasins to the street sewer storms, drainage systems be stress western tributary. the inlet time is 15 minutes. tested using design storms calculated on the basis of a 20% increase of the · In the absence of detail lot Temperature City’s IDF curves rainfall values. configuration and building size and Modifications to the drainage system With respect to temperature, the Aquatic position, the total imperviousness of would be required if severe flooding Habitat Assessment indicates that external future urban areas is to be of properties is identified. temperature mitigation measures should used for detailed design of not be required for the outflows from infrastructure for the subject phase of future SWM facilities. development. The imperviousness

Aquafor Beech Ltd. August 2015 – Final Report 101 4. 2 CONVENTIONAL SWM · Two end-of-pipe stormwater 1. Eastern SWM Facility management facilities. SYSTEM CONCEPT 2. Western SWM Facility · Rehabilitation of the existing Burma Per the MSS (IBI, 2015) the proposed The locations of the facilities are Road SWM facility (originally redevelopment of former CFB Rockcliffe illustrated on Figure 25 and Figure 26. constructed in the early 1990’s) will be comprised of low, medium and high Figures 27 and Figures 28 illustrates the density residential, commercial, · Three (3) Dry Ponds for water proposed end-of-pipe SWM facility layout, institutional and park space. As part of the quantity control grading and facility attributes. development, the existing combined The MSS also recognizes that LID Both facilities have been designed to sewer and storm sewer systems will be techniques are being considered for the provide an Enhanced Level of Protection. eliminated, with installation of new site that the SWM system concept as According to the MOE Stormwater independent storm and sanitary services. presented in the MSS is designed with the Management Planning and Design Manual The proposed storm system will be flexibility to incorporate LID techniques. (March 2003). designed to provide capacity for the Dual Drainage Concept existing external flows that are currently It should be noted that in addition to the conveyed through former CFB Rockcliffe, Dual drainage design features a Rockcliffe development, the Eastern SWM including outflows from the northeastern combination of on-site detention (surface Facility provides water quality treatment portion of the Montfort Hospital, the ponding) with inlet control devices (ICDs) for the lands tributary to the Burma Road Burma Road SWM Facility, and surface and direct conveyance with no ponding. It SWM Facility (a water quantity facility flows from the external lands south and accommodates both minor (pipe) and only) and for the future museum site. The east of the site. major (surface) stormwater runoff. Figure Western SWM Facility provides water 25 and Figure 26 illustrate the proposed quality treatment for the portion of the The conceptual stormwater management minor and major system per the MSS. Montfort Hospital site tributary to the system incorporates standard urban Montfort SWM Facility (a water quantity drainage design and stormwater End-of-Pipe SWM Facilities facility only). management features that can be To address the water quantity and quality summarized: Additional detail with respect to the end- requirements of the redeveloped former of-pipe facilities as described in the MSS · As a dual drainage concept CFB Rockcliffe site, the MSS (IBI, 2015) (IBI, 2015) is provided in the subsequent incorporating both a minor system proposes that two end-of-pipe SWM sections. and major system; facilities be provided.

102 Aquafor Beech Ltd. August 2015 – Final Report Eastern SWM Facility It is proposed that the Eastern SWM to birds, possibly augmented with floating Facility provide baseflow augmentation to islands to further discourage waterfowl. As indicated on Figure 26, the trunk storm the Eastern Creek by means of a small sewer servicing the eastern portion of the diameter pipe. Based on a volumetric Outflow from the facility is conveyed study area extends north from the calculation, 51,081cu-m/year is to be downstream via the Hemlock Road culvert, development towards the escarpment conveyed from the pond to the creek. The where it will flow overland towards the bordering the study area. It is proposed in MSS recommends that this be confirmed existing Aviation Parkway culvert. the MSS (IBI, 2015) that the 3000 mm x at the detailed design stage, supported by Downstream, flow will discharge to the 3600 mm trunk storm sewer will terminate continuous modeling. Western Creek via the Aviation Parkway at the top of the escarpment and the culvert during frequent storm events. runoff will cascade to the SWM facility It is important to notes that the increase During infrequent storm events, flow in below via a waterfall. in flow resulting from development will be excess of the Aviation Parkway culvert directed to the Ottawa River, away from capacity will be conveyed east via the The Eastern SWM Facility (Figure 28) is the two creeks, via a 2400 mm diameter proposed channel-pipe configuration designed as a wet pond, is comprised of a storm sewer. (Figure 29). stilling basin, and a wet cell, with an outlet structure to a new storm sewer to the Western SWM Facility As discussed previously, the estimated Ottawa River. The proposed design creates bankfull flows in the downstream Western a series of smaller open water surfaces, The Western SWM Facility is located at the Creek could range between 0.70cms and considered less desirable to birds, northwestern corner of the development, 1.4cms (DST, September 2013). The MSS augmented by floating islands. abutting Hemlock Road to the south. notes, that from a fluvial geomorphology perspective, outflow through the Aviation Runoff will flow from the two inlets to As discussed previously, the estimated Parkway culvert during the 25mm storm sediment forebays, from which flow is bankfull flows in the Eastern Creek could event is 0.37cms, a rate that corresponds conveyed to the main cell of the facility. range between 0.50cms and 2.5cms (DST, to less than bankfull estimates. September 2013). From a fluvial Downstream of the southern sediment geomorphology perspective the flow forebay, the Southwest Channel will tie generated by the contributing drainage into the main cell of the facility. Similar to areas during the 25mm storm event is the Eastern SWM Facility, the proposed 0.56cms, which is at the lower end of the design creates a series of smaller open bankfull estimates. water surfaces, considered less desirable

Aquafor Beech Ltd. August 2015 – Final Report 103

Figure 25: Post Development Conditions Drainage Area Plan – Minor System Connectivity

104 Aquafor Beech Ltd. August 2015 – Final Report

Figure 26: Post Development Conditions Drainage Area Plan – Major System Connectivity

Aquafor Beech Ltd. August 2015 – Final Report 105

Figure 27: Eastern SWM Facility – Layout, Grading and Facility Figure 28: Western SWM Facility – Layout, Grading and Facility Attributes Attributes

106 Aquafor Beech Ltd. August 2015 – Final Report Special Design Area Dry Ponds 2015) is provided in the subsequent sections. Stormwater runoff from the Special Design Three (3) dry ponds are proposed across Area (Block 44, refer to Figure 2.0) is to be the site for the purpose of surface storage Park Dry Pond provided with its own stormwater and flow routing (Figure 26 and Figure 27): management system, which proposes the The Park Dry Pond is proposed to be use of a storm sewer for conveyance 1. Park Dry Pond located in the park block identified as Block 38 (Figure 2.0). Total flow from outletting to the Eastern Creek and an 2. Eastern Dry Pond OGS system for water quality control. The Foxview, major flow from a portion of 3. Central Dry Pond specific details of the stormwater Thorncliffe Village, and major flow from management for this Special Design Area In addition, in Block 22 (area PH1D), a the southeast of the study area will be 3 will be determined at the detailed design park, will provide 230 m of storage during conveyed overland to the park dry pond stage. the 100 year event. Major flow from for attenuation, prior to being released to portions of the study area will be directed the minor system. The areas contributing While the MSS provides a conventional to the three (3) dry ponds for attenuation major flow to the park dry pond are SWM serving approach, it is envisioned prior to release, specifically 16.2, 2.5 and indicated on Figure 26. that the Special Design Area will be 0.5 m3/s for the 100 year event for the The conceptual plan and cross-section of developed (Phase 3 - starting in the year Park, Eastern and Central dry ponds the park dry pond are presented on 2024) as a full LID development without respectively. the need for conventional stormwater Figures 29. The facility is divided into management to service the minor systems The infiltration potential of these ponds three cells, separated by berms provided (concrete piping networks) or major are discussed in Section 5.0 of this report, by culverts. The berms have been system flows (SWM ponds). however, the storage volume designated incorporated into the design to allow for for the ponds is for major system storage. pedestrian access to the rest of the park Types of LID controls proposed as part of The MSS (IBI, 2015) acknowledges that the south of the dry pond. The three cells are the demonstration project are described in functional design for the major system designed with flat bottoms, ranging from Section 5.13 – Specific Projects. storage provides flexibility in terms of the 88.5m at the upstream, 87.7m at the potential future use for LID techniques. intermediate cell, and 87.5m at the downstream cell. Additional detail with respect to each dry

pond facility as described in the MSS (IBI,

Aquafor Beech Ltd. August 2015 – Final Report 107 T he MSS (IBI, 2015) notes that the 3H:1V. The outlet control structure, 100 year storm event, it is estimated the proposed design provides flexibility at the located at the western-most point of the water level will reach 82.5m, detailed design stage, should the dry pond pond, will convey flow to the storm sewer corresponding to an average depth of also be used for infiltration purposes. located in the adjacent street. The 0.3m. The total volume utilized is 560m3. Otherwise, a longitudinal slope can be elevation of the outlet control structure is The conceptual plan and cross-section of introduced across each of the cells. set at 85.3m, slightly below the invert of the dry pond are presented on Figure 31. the pond, resulting in there being no On the north, the side slopes of the facility permanent pool in the pond. Outflow from Southwest Conveyance Channel are proposed at 3H:1V. On the south, a the facility is restricted to 147 l/s. During A conveyance channel is proposed around 0.7m armour stone wall is proposed. The the 100 year storm event, it is estimated the south and west of the study area, outlet control structure, located at the the water level will reach 86.1m, henceforth referred to as the Southwest western-most point of the facility, will corresponding to an average depth of Channel. It extends west from Codd’s convey flow to the storm sewer located in 0.6m. The total volume utilized is 1610m3. Road, between the redevelopment and the adjacent street. The elevation of the The conceptual plan and cross-section of the Montfort Hospital Woods, from where outlet control structure corresponds to the pond are presented on Figure 30. the invert of the facility (87.5m), resulting it will extend north prior to releasing to in there being no permanent pool in the Central Dry Pond the Western SWM Facility (Figure 25 and facility. Outflow from the facility is Figure 26). Major flow runoff from a restricted to 160 l/s. During the 100 year The central dry pond is located in the portion of the study area will be directed storm event, it is anticipated the average north-central of the site. The bottom of to the channel, as will runoff from depth of ponding will be 0.6 m. The total the pond is flat, with an invert of 82.3m. Fairhaven, the Montfort Hospital Woods, volume utilized is 3,000m3. Figure 29 The side slopes of the pond are proposed outflow from the Montfort Hospital SWM illustrates the Park Dry Pond plan view and at 3H:1V. Outflow from the pond will be Facility, and major flow from the cross-section. conveyed from the western-most point of northeastern portion of the hospital site. the pond by either pipe or swale. The Eastern Dry Pond outflow will be conveyed to the Eastern The channel consists of a trapezoidal SWM Facility. The elevation of the outlet cross-section with a bottom ranging in The eastern dry pond is located in the corresponds to the invert of the pond width from 1-3m, and 3H:1V side slopes northeast of the site. The bottom of the (82.3m), resulting in there being no that tie into existing grades to the south pond is flat, with an invert of 85.5m. The permanent pool in the pond. Outflow from and west and the proposed development side slopes of the pond are proposed at the pond is restricted to 98 l/s. During the to the north and east. The proposed

108 Aquafor Beech Ltd. August 2015 – Final Report longitudinal slope of the channel ranges from between 0.5 and 1.7%. At its downstream end, the total flow to be conveyed to the channel is 2.9cms. The estimated depth of flow in the channel during the 100 year event is 0.6m. The conceptual cross-section is indicated on Figure 32.

The MSS (IBI, 2015) notes that the proposed design provides flexibility at the detailed design stage, should the Southwest channel also be used for infiltration purposes.

All analysis, modelling in regards to the dual drainage concept, end-of-pipe SWM facilities, Special Design Areas, dry ponds and channel characteristics are detailed in Section 6.0 of the MSS (IBI, 2015).

Aquafor Beech Ltd. August 2015 – Final Report 109

Figure 29: Park Dry Pond - Plan View and Cross Section A-A

110 Aquafor Beech Ltd. August 2015 – Final Report

EXISTING ROADWAY

Figure 30: Eastern Dry Pond - Plan View and Cross Section A-A

Aquafor Beech Ltd. August 2015 – Final Report 111

Figure 31: Central Dry Pond - Plan View and Cross Section A-A

112 Aquafor Beech Ltd. August 2015 – Final Report

Figure 32: Southwest Channel – Typical Channel Section

Aquafor Beech Ltd. August 2015 – Final Report 113 4. 3 CONVENTIONAL SWM SYSTEM PHASING

The development of the former CFB Rockcliffe site will occur in a phased sequence spread over a number of years as demonstrated in Figure 33. Additionally, Phase 1 will be divided into two: Phase 1A and Phase 1B. Phase 1A will include Codd’s Road to the City Centre area and the lower density residential areas immediately west of Codd’s road.

Phase IA Stormwater Infrastructure

Local minor storm sewers will be needed to properly service Phase 1A. All stormwater runoff from this phase will be routed to the new Eastern SWM Facility, which will need to be constructed as part of Phase 1A. Also, the western cell of the proposed Park Dry Pond will need to be Figure 33: Development Phasing Plan constructed as part of Phase 1A in order to accept major storm runoff from Codd’s Road.

114 Aquafor Beech Ltd. August 2015 – Final Report