Tsawwassen First Nation Integrated Rainwater Management Plan FINAL REPORT

Transcription

1 Tsawwassen First Natin Integrated Rainwater Management Plan FINAL REPORT

2 INTEGRATED RAINWATER MANAGEMENT PLAN PREPARED FOR: Tsawwassen First Natin ATTENTION: PREPARED BY: Ed Chanter, Directr f Lands 1926 Tsawwassen Drive Tsawwassen, B.C. V4M 4G2 Urban Systems Ltd Avenue Surrey, BC V3T 5T3 CONTACT PERSON: Samantha Ward, P.Eng. sward@urbansystems.ca PHONE: ext DATE: December 19, 2013 This reprt is prepared fr the sle use f Tsawwassen First Natin. N representatins f any kind are made by Urban Systems Ltd. r its emplyees t any party with whm Urban Systems Ltd. des nt have a cntract. Cpyright USL File #

3 Final Reprt Executive Summary An Integrated Rainwater Management Plan (IRMP is a cmprehensive plan that examines the interrelatinships between drainage servicing, land use planning, and envirnmental prtectin. Its purpse is t utline an apprach t supprt and prmte the grwth f a cmmunity in a way that maintains, r ideally enhances, the verall health f a watershed. By applying an integrated apprach, an IRMP can be used t link watershed and stream health t land use and plicy decisins. Further, as a plicy level dcument, an IRMP can be a pwerful tl that supprts a cmmunity s path twards achieving its visin fr the future. Tsawwassen First Natin (TFN is pised t experience cnsiderable grwth and develpment ver the next few decades. This grwth will directly result in the need t prvide imprved drainage services and prtect envirnmental assets, all while allwing develpment t prceed. The IRMP prvides the pprtunity fr TFN t utline its rainwater management gals and bjectives, in a practive manner, t guide future develpment. It als satisfies TFN s cmmitments under the existing services agreements between TFN and the Crpratin f Delta (Delta, and has been prepared in accrdance with Metr Vancuver s Integrated Liquid Waste and Resurce Management Plan requirements. TFN lands are situated next t the Strait f Gergia (Salish Sea and are brdered by Delta n the nrth, east and suth sides. TFN lands are bisected near the nrth and suth limits by the Prt Metr Vancuver Rberts Bank Causeway (Deltaprt Way and the BC Ferries Causeway (Highway 17A, respectively. The ttal area f TFN lands (pst-treaty; as f September 2011 is 662 hectares (ha (identified as the Tsawwassen Lands in the TFN Land Use Plan. While the scpe f the IRMP mainly fcuses n TFN lands, it is imprtant t understand hw TFN lands interact with and are affected by the surrunding area. Therefre, the IRMP als cnsiders external lands that are hydraulically cnnected t TFN; that is, rainwater runff generated by these external lands is cnveyed thrugh TFN lands and discharged t the Strait f Gergia. The external lands are lcated within Delta and are rughly bunded by Deltaprt Way t the nrth, Bundary Bay t the east, 14 Avenue t the suth, and 52 Street t the west. TFN lands and external lands tgether cmprise the Study Area fr the IRMP (apprximately 1,716 ha in ttal. The IRMP has been rganized int fur stages; the purpse and utcmes f each stage is highlighted in Table E.1 belw. Table E.1: IRMP Stages STAGE TITLE PURPOSE AND OUTCOMES Stage 1 What Des TFN Have? (Inventry f Existing Systems Summarize key features and prperties f the Study Area Highlight pprtunities and cnstraints Identify key issues fr the IRMP t address Page vii

4 Final Reprt STAGE TITLE PURPOSE AND OUTCOMES Stage 2 Stage 3 Stage 4 What Des TFN Want? (Visin, Gals and Objectives Hw Des TFN Put The IRMP Int Actin? (Assessment, Analysis and Implementatin Hw Des TFN Ensure That The IRMP Stays On Target? (Mnitring and Adaptive Management Summarize anticipated future land uses in the Study Area Articulate a visin (supprted by gals and bjectives fr rainwater management that meets cmmunity needs and guides the IRMP prcess Identify, assess and present the recmmended servicing apprach(es fr future develpment cnditins Outline perfrmance targets and design criteria Develp a clear framewrk fr implementatin Prepare cst estimates fr recmmended wrks Identify perfrmance indicatrs fr key IRMP cmpnents Outline mnitring and assessment prgrams Describe an adaptive management prcess that TFN can use t mdify the implementatin strategy if, thrugh mnitring and assessment prgram results, TFN determines that the IRMP visin, gals and bjectives are nt being met Stage 1 What des TFN have? The IRMP prvides an inventry f existing systems, including drainage infrastructure (pen ditches, culverts, sewers, pump statins and dikes, land use, regulatry framewrk (laws and regulatins, service agreements, envirnmental features (aquatic and freshre habitat, wildlife, vegetatin, getechnical (sil characteristics, slpe stability, hydrgelgy (grundwater and aquifer, and water and sediment quality. The majrity f TFN lands are currently undevelped r used fr agricultural purpses, with remaining lands cnsisting f husing, cmmunity facilities and limited cmmercial uses. The remainder f the Study Area primarily cnsists f agricultural lands, althugh residential, recreatinal (glf curses and cmmercial uses are als present. There are several future develpments planned n TFN lands, which will result in an increase in impervius (hard surface area in the rder f 260 hectares ver existing cnditins. Per Delta s Official Cmmunity Plan (OCP, Delta will nly experience a 19 hectare increase in impervius area under future cnditins. The regulatry framewrk varies depending n whether lands are lcated within TFN r Delta. Reginal, Prvincial and Federal statutes and regulatins may als be relevant. In general, TFN Regulatins and Delta Bylaws cver many f the same tpics; hwever, TFN s Regulatins tend t be brader in scpe and definitin whereas Delta Bylaws tend t be mre defined and prescriptive. Page viii

5 Final Reprt The drainage netwrk within the lwland prtins f the Study Area primarily cnsist f intercnnected ditches, with culverts at rad and driveway crssings. The netwrk cllects and cnveys rainwater and irrigatin runff t pump statins, which in turn discharge flws t the Strait f Gergia. In the upland prtins f the Study Area, the drainage netwrk generally cnsists f an undergrund strm sewer system, with limited segments f radside ditching. TFN lands are currently prtected frm cean inundatin by a dike system that separates the cmmunity frm the Strait f Gergia. The existing dike system generally meets current Prvincial fld prtectin requirements; hwever, recently published Prvincial dcuments n climate change adaptatin suggest that fld prtectin infrastructure n TFN lands may need t be altered significantly ver the next several decades t respnd t climate change. Frm an envirnmental perspective, the ditches in the Study Area are channelized and straight, have pr water quality characteristics, cntain n characteristic features f salmnid-bearing stream habitat, and largely functin as a cnveyance netwrk fr the surrunding lands and rad system. By cntrast, the freshre marine envirnment (t which the internal drainage netwrk discharges t cntains high value habitat fr birds, fish and ther wildlife. The majrity f vegetated areas within TFN lands cnsist f cultivated agricultural r fallw lands, with stands f trees n the Tsawwassen Bluff escarpment and alng larger drainage ditches. Watercurses and assciated riparian habitat have been substantially mdified since settlement and develpment f agriculture. Remaining riparian habitat is f imprtant eclgical value as it prvides habitat fr a variety f mammal and bird species, stabilizes ditch banks, and filters runff frm adjacent lands. TFN lands prvide habitat fr a variety f wildlife species including thse assciated with marine, intertidal, grassland, riparian and frest habitat types. The Study Area supprts amphibians (frgs, salamanders, garter snakes, a wide variety f birds, mammals (mice, beavers, cytes, raccns and invertebrate species. TFN lands, adjacent farmland and freshre have been identified as an Imprtant Bird Area (IBA; apprximately 264 bird species have been dcumented within the Bundary Bay Rberts Bank Sturgen Bank IBA. Within the lwland prtins f the Study Area, the natural sil cnditins likely cnsist f a thin layer f tpsil, verlying up t abut 3 metres f silt t clayey silt, verlying abut 50 metres f interlayered sand and silt layers. Sme areas have been previusly filled, and the quality and cmpsitin f such fill has nt been characterized, althugh is likely highly variable. The water table is high and is likely near the surface f the natural sils during the wetter mnths r when irrigated. Grundwater flw directins are cmplex as they are dependent n the water levels in the ditches (which are cntrlled by the pump statins and the water levels in the cean relative t the water table elevatin in the sil. Within the upland prtins f the Study Area, the steep slpes f the Tsawwassen Bluffs are subject t a slw prcess f slughing and slpe regressin that is expected t cntinue. Grundwater seepage discharge is cmmn n the slpes at and near the slpe te f the escarpment. This cntact and seepage discharge frms the initiatin znes f active shallw debris slides. Page ix

6 Final Reprt A limited water and sediment quality sampling prgram was cnducted as part f the IRMP. Measured levels f disslved xygen and ttal suspended slids suggest that these parameters are limiting factrs fr fish in lcal ditches. There were exceedances fr sme chemical and bacterilgical water quality samples, as well as exceedances fr ttal rganic carbn, metals, and hydrcarbn cnstituents in sediment samples. Based n the inventry f existing systems in the Study Area, the key issues identified t cnsider in the IRMP are: Cnveyance and Pumping Water Quality On-Lt Rainwater Retentin Fld Prtectin Stage 2 What des TFN want? TFN s lcatin, the surrunding natural envirnment, and the cmmunity s cnnectin t the land and the cean all lend themselves t the pprtunity t shwcase sustainable and innvative appraches t rainwater management. Thrugh discussins with TFN Staff, Cuncil and Cmmunity Members, a Visin fr Integrated Rainwater Management n TFN lands has been develped: Tsawwassen First Natin s (TFN apprach t Rainwater Management supprts and prmtes the balanced grwth f the cmmunity in a way that psitively cntributes t the verall health f the surrunding envirnment. Rainwater is viewed as a resurce, and develpment capitalizes n the pprtunities t implement innvative Rainwater Management techniques while prviding effective drainage service that des nt impede the use and enjyment f adjacent lands by thers. The cllective Rainwater Management system allws the surrunding envirnment t thrive, supprting wildlife, aquatic species, and vegetatin by prviding habitat, fd and migratin rutes. TFN s histric cnnectin t the land and the sea is reflected thrugh the prliferatin f naturalized drainage systems thrughut the cmmunity. Aside frm their intended functins, these systems als act t educate and infrm cmmunity members f the imprtance f Rainwater t humans and the natural envirnment. TFN is prud f the example that the cmmunity has set twards Rainwater Management. This visin is supprted by several gals and bjectives related t rainwater management, envirnment, getechnical, planning and land use, and landscape. Stage 3 Hw des TFN put the IRMP int actin? The IRMP assessed the hydrlgical characteristics f TFN lands and the verall Study Area, alng with the hydraulic perfrmance f the drainage infrastructure that services thse lands under existing and future land use cnditins. Varius scenaris have been assessed their ability t adequately service the TFN cmmunity and maintain a cmparable level f drainage service (as cmpared t existing Page x

7 Final Reprt develpment cnditins t the verall Study Area. Climate change (sea level rise, rainfall pattern distributin changes and land subsidence has been cnsidered as part f the future servicing analyses. The recmmended servicing apprach (Figure ES.1 t supprt future grwth and develpment n TFN lands and the verall Study Area cnsists f the fllwing: Increase ttal capacity f Brandrith Drainage Pump Statin frm 2.8 m 3 /s t 5.2 m 3 /s (plus existing jckey by retrfitting the existing statin Cnstruct a new drainage pump statin fr the TFN Industrial Lands with a pumping capacity f 2.5 m 3 /s Upgrade several culverts alng the 48 th Street and 52 nd Street drainage channels t increase cnveyance capacity Prvide 300mm depth f amended tpsil in all pervius areas within new develpment (bth private and public areas Discnnect impervius areas t the greatest extent pssible (e.g., discharge rf dwnsputs t splash pads fr single family and multi-family residential develpment, grade sites t drain impervius areas t pervius areas Maximize pprtunities t decrease impervius surfaces (e.g., reduce rad widths and parking areas, use prus paving materials fr driveways, patis, parking pads, n-street parking areas, etc. Review pprtunities t retain rainwater runff generated by impervius surfaces thugh the use f rainwater management features (RMFs including rain gardens, vegetated biswales, rainwater harvesting techniques, etc. Cst estimates fr recmmended drainage infrastructure, summarized in Table E.2 belw, are representative f Class D cst estimates and include 35% cntingency and 12% engineering, but exclude GST. Table E.2: Recmmended Drainage Infrastructure Cnstructin Cst Estimates ITEM TOTAL Retrfit Brandrith Drainage Pump Statin fr 5.2m 3 /s capacity $ 1,259,000 TFN Industrial Lands Drainage Pump Statin (2.5 m 3 /s capacity $ 2,498,000 CI01: Prvide drainage cnnectin acrss Highway 17A (allwance $500,000 CU01: Upgrade existing 600mm t 900mm HDPE Culvert $ 56,000 CU02: Upgrade existing 600mm t 900mm HDPE Culvert $ 47,000 CU03: Upgrade existing 600mm t 900mm HDPE Culvert $ 47,000 CU04: Upgrade existing 600mm t 900mm HDPE Culvert $ 50,000 CU05: Upgrade existing 600mm t 1050mm HDPE Culvert $ 46,000 Page xi

8 53 Street 54 Street 56 Street " T Rbert's Bank Way New Industrial Lands Pump Statin (Capacity = 2.5m 3 /s S t r a i t f G e r g i a ( S a l i s h S e a " T 28B Avenue 41B Street Falcn Way Deltaprt Way 27B Avenue CU10: Upgrade frm 1.2m Ø t 2.4m x 1.5m bx culvert Tsawwassen Tsawwassen Drive Nrth CU11: Upgrade frm 1.5m Ø t 2.4m x 1.5m bx culvert PU01: Retrfit Brandrith pump statin fr 5.2m 3 /s capacity " T Drive t h Su Eagle Way Pacific Drive CU01: Upgrade frm 0.6m Ø t 0.9m Ø culvert " T 48 Street 28 Avenue CU02: Upgrade frm 0.6m Ø t 0.9m Ø culvert CU04: Upgrade frm 0.6m Ø t 0.9m Ø culvert CU06: Upgrade frm 0.6m Ø t 1.05m Ø culvert CU09: Upgrade frm 0.6m Ø t 1.05m Ø culvert NuLelum Way 16 Avenue 52 Street 52 Street CI01: Prvide drainage cnnectin acrss Highway 17A 53A Street Deficient Culvert: Upgrade recmmended fr cnsideratin by Crpratin f Delta 28 Avenue CU03: Upgrade frm 0.6m Ø t 0.9m Ø culvert CU05: Upgrade frm 0.6m Ø t 1.05m Ø culvert CU07: Upgrade frm 0.6m Ø t 1.05m Ø culvert CU08: Upgrade frm 0.9m Ø t 1.05m Ø culvert 18 Avenue 15B Avenue 12th Avenue 56 Street " T 17A Avenue 16 Avenue 57B Street Highway 17A 21 Avenue Farrell Avenue Farrell Crescent Highway 17A Enderby Avenue 28 Avenue Deficient Culvert: Upgrade recmmended fr cnsideratin by Crpratin f Delta B u n d a r y B a y Legend Mdeled Culverts " T Lg Mdeled Pump Statins Mdeled Ditch Netwrk Mdeled Pipe Netwrk Watercurses identified within the Drainage and Irrigatin Services Agreement. Tsawwassen First Natin (TFN lands IRMP Study Area Nte: Orthpht n west half f figure was taken n July 31, Orthpht n east half f figure was taken in BC Ferries Causeway Kuma Crescent Skana Drive Pacific Driv e 8A Avenue Integrated Rainwater Management Plan Recmmended Drainage Infrastructure Imprvements THE ACCURACY & COMPLETENESS OF INFORMATION SHOWN ON THIS DRAWING IS NOT GUARANTEED. IT WILL BE THE RESPONSIBILITY OF THE USER OF THE INFORMATION SHOWN ON THIS DRAWING TO LOCATE & ESTABLISH THE PRECISE LOCATION OF ALL EXISTING INFORMATION WHETHER SHOWN OR NOT. U:\Prjects_VAN\2177\0040\01\D-Drafting-Design-Analysis\GIS\Prjects\MXD\Current\MdelUpdate_Nvember2013\Figure ES.1 - Recmmended Drainage Infrastructure Imprvements.mxd Last updated by: bpauls n December 18, 2013 at 3:47:29 PM ,000 Meters [ Figure ES.1

9 Final Reprt ITEM TOTAL CU06: Upgrade existing 600mm t 1050mm HDPE Culvert $ 46,000 CU07: Upgrade existing 600mm t 1050mm HDPE Culvert $ 50,000 CU08: Upgrade existing 900mm t 1050mm HDPE Culvert $ 61,000 CU09: Upgrade existing 600mm t 1050mm HDPE Culvert $ 102,000 CU10: Upgrade existing 1200mm t 2.4m x 1.5m Bx Culvert $ 132,000 CU11: Upgrade existing 1500mm t 2.4m x 1.5m Bx Culvert $ 147,000 Subttal $ 5,041,000 35% Cntingency $ 1,764,000 12% Engineering $ 605,000 TOTAL $ 7,410,000 Wrks culd be funded thrugh TFN s ffsite levies (OSL prgram, r thrugh a future rainwater management utility, depending n the nature f the wrk, the benefitting area, and TFN s preference fr cst recvery. Three tiers f water quality treatment are recmmended fr future develpment: Basic Cntrl fcuses n remval f ttal suspended slids (with assciated pllutants that are attached t thse sediments Oil Cntrl fcuses n remval f petrleum hydrcarbns Enhanced Cntrl fcuses n remval f disslved metals (e.g., cpper and zinc The level f water quality treatment t be applied will depend n the prpsed land use. Future develpment at TFN als prvides an pprtunity t incrprate wildlife mvement linkages int the landscape. Envirnmental enhancement effrts shuld fcus n wildlife habitat imprvements and linkages, which in turn shuld als imprve habitat cnditins fr nn-salmnid fish species that may be present in the ditch netwrk. Develpments shuld maintain aquatic habitat where feasible, with pririty given t retentin f Class A ditches. Cmpensatin fr habitat lst due t ditch infilling can best be achieved by designating specific areas fr newly created habitat, and placing these within r adjacent t larger retained r managed habitat. Opprtunities t achieve multiple gals and bjectives thrugh shared spaces shuld be explred. In particular, applying a multi-functinal crridr netwrk apprach t radways (48 th Street, lcal rads and the prpsed Great Blue Hern Way is encuraged. These spaces shuld strive t achieve drainage, envirnmental and landscape gals and bjectives. Page xiii

10 Final Reprt The IRMP als identifies a suite f regulatry amendments and additins t enhance TFN s supprt f integrated rainwater management. High pririty regulatry amendments and additins are listed in Table E.3. Table E.3: High Pririty Regulatry Amendments and Additins RECOMMENDATIONS 1. Finalize the MMCD Design Guideline Manual and Cnstructin Specificatins Supplementary Specificatins dcument 2. Amend the Drainage and Sewer Regulatin 3. Establish an Ersin and Sediment Cntrl Regulatin 4. Update the Capital Plan 5. Update the Offsite Levies Regulatin 6. Amend the Landscape Guidelines With sea levels predicted t rise and land predicted t subside (sink in the future, the current fld prtectin (dike system will nt be adequate t prtect the TFN cmmunity in the lng-term. Therefre, ptins t prvide imprved fld prtectin t the cmmunity shuld be explred. Building n the IRMP, TFN shuld undertake a fld prtectin study t review and assess the suitability f varius alternatives fr prviding fld prtectin t the TFN cmmunity in the future. In-depth drainage studies fr TFN s cmmunity lands and the Tsawwassen Bluffs area are als recmmended t reslve specific drainage cncerns with these areas. Stage 4 Hw des TFN ensure that the IRMP stays n target? Perfrmance indicatrs and targets are needed t evaluate prpsed develpment schemes and t determine the level f success in achieving the IRMP gals and bjectives. Primary perfrmance indicatrs and targets are listed in Table E.4. Table E.4: IRMP Perfrmance Indicatrs and Targets PERFORMANCE INDICATOR Frequency and Extent f Flding Water and Sediment Quality Open Channel Riparian Health TARGET Nt t exceed current levels Stabilize, r ideally imprve, ver current cnditins Minimum 80% survival rate f native (existing r planted vegetatin Minimize / remve invasive species within riparian znes Page xiv

11 Final Reprt The IRMP utlines a cmprehensive mnitring prgram t assess the ability f future develpment t meet the IRMP visin, gals and bjectives as wrks and prgrams are implemented. Precipitatin, water levels, flw rates, water and sediment quality, riparian habitat, and intertidal and marine habitat cnditin mnitring are all recmmended, alng with annual assessments and reprting. Apprximately $150,000 is required t establish the mnitring prgrams and cnduct an initial year s review. Apprximately $30,000 t $40,000 per year is estimated t maintain the prgrams thereafter. This excludes TFN s internal csts assciated with administratin and recrds. The IRMP als utlines an adaptive management framewrk t assist in identifying issues and utlining crrective actins shuld the mnitring prgram results indicate that IRMP gals and bjectives are nt being met. Page xv