Presentation on theme: "Potomac Ridge Stormwater Management Project"— Presentation transcript:
1Potomac Ridge Stormwater Management Project Millions have lived without love. No one has lived without water.Turkish businessman, 1998October 7, 2013 Public MeetingMontgomery County Department of Environmental ProtectionWatershed Management Division
2Today’s Agenda Introductions Paul Bogle – Senior Engineer, Montgomery County DEPDarian Copiz – Watershed Planner; Montgomery County DEPDoug Streaker – Project Engineer; BiohabitatsJeff Blass – Project Designer; Charles P. Johnson EngineeringBackground Information – Why County is Doing ThisPotomac Ridge Stormwater Management OverviewProject ObjectivesProject Costs and BenefitsDesign and Permitting TimelineWhat to Expect During Construction
3Sources of Water About 97% is salt water About 2% is frozen Only 1% is available for drinking water95% from groundwater across the Country32% from groundwater, 68% from surface water in MarylandPotential for greater impacts from runoff in MarylandDrinking water protection and urban nonpoint source pollution. Materials on page 50 and 51 of the Resource Packet.About 97% is salt water on the earth. 2% is in the ice caps. Only the remaining 1% is available for drinking water. Of this 1%, groundwater accounts for about 95% of the nation's freshwater resources, eventually flow into surface water bodies. It can bubble out of the ground as a spring or it can be pumped from wells.In Maryland, about 68% of the population is served from surface sources, the remainder from wells, either individual or community systems.Do you know where your household drinking water comes from?Rivers, lakes, reservoirs, springs, and groundwater wells.Aquifers: underground rivers of water formed from water that seeps from the land surface through the soil layers and becomes trapped between rock formations.
4Montgomery County, MD 500 sq. miles 1,000,000 people 11/2/2011Montgomery County, MD500 sq. miles1,000,000 peopleSecond only to Baltimore City within Maryland in average people per square mile184 languages spokenAbout 12% impervious surface overallAbout the size of Washington DCOver 1,500 miles of streamsTwo major river basins:PotomacPatuxentEight local watershedsDistrict of ColumbiaBrief history and tidbits about MoCo.EXPLAIN imperviousPotomac 88% of MCPatuxent 12% of MCOf the 184 languages spoken the top 5 non English spoken are: Spanish, Chinese (Mandarin), Korean, Vietnamese, Amharic (Ethiopia)Impervious: Not allowing water to soak through the ground.
5What is a Watershed?A watershed is an area from which the water above and below ground drains to the same place.Different scales of watersheds:Chesapeake BayEight local watershedsNeighborhood (to a storm drain)
6Volume/Timing of Runoff 11/2/2011What is Runoff?Water that does not soak into the ground becomes surface runoff. This runoff flows over hard surfaces like rooftops, driveways and parking lots collecting potential contaminants and flows:Directly into streamsInto storm drain pipes, eventually leading to streamsInto stormwater management facilities, then streamsBrief history and tidbits about MoCo.EXPLAIN imperviousStormwater is water that originates from storms… becomes runoffTwo Major Issues:Volume/Timing of RunoffWater Quality
7What is the County doing to protect our Streams? 11/2/2011What is the County doing to protect our Streams?Must meet regulatory requirementsFederal Clean Water Act permit programMS4 = Municipal Separate Storm Sewer SystemApplies to all large and medium Maryland jurisdictionsCounty programsRestore our streams and watershedsAdd runoff managementMeet water quality protection goalsReduce pollutants getting into our streamsEducate and engage all stakeholdersIndividual actions make a differenceFocus on watersheds showing greatest impactsFederal Clean Water Act NPDES: National Pollutant Discharge Elimination System MS4: Municipal Separate Storm Sewer System PermitMS4 Permit sets priorities for all Watershed7
8MS4 permit, what is it? Montgomery County is responsible for: What goes into our storm drain pipesWhat comes out of themWhat flows into the streamsRequires additional stormwater management for 20 percent of impervious surfaces (4,292 acres = 6.7 square miles). That’s about three times the size of Takoma Park.That’s equivalent to 3,307 football fields!
9Project Selection Ponds constructed in early 1980s Located in a key watersheds (Muddy Branch, Watts Branch) for pond retrofitsPonds are at or near the end of service lifeMeet current safety and design standardsOpportunity for water quality treatment and ecological benefits
11Rich Branch (Muddy Branch) Potomac Ridge10876Rich Branch (Muddy Branch)1088710891Can add own photo for your own projects.10847Sandy Branch(Watts Branch)
12Project Objectives STORMWATER MANAGEMENT STREAM PROTECTION MAINTENANCE Add permanent pool for water quality where feasibleSTREAM PROTECTIONModify outlet works to better regulate pond discharge and protect Sandy Branch and Rich Branch streamsMAINTENANCEReplace existing risers with water-tight structuresReplace dam embankment or install impervious linerInstall internal drain in downstream embankmentsAESTHETICS/ENVIRONMENTLandscape the pond to improve aquatic habitat and aestheticsAugment existing environmental features such as forest and wetlands where possibleCan add own photo for your own projects.
13Stormwater Pond Drainage Areas 60.4 Acres58.8 Acres25% Impervious16% ImperviousPond 10876Pond 108917.9 Acres47.3 Acres22% Impervious20% ImperviousCan add own photo for your own projects.
14Pond 10847 Stormwater Management Dry Pond 8’ High Earth Embankment Dam Adjacent residential propertiesDoes not meet current SWM requirements to achieve any MS4 credit.Long drainage swale inflow to north end.Existing Metal Outlet StructuresLarge Outlet Control OrificeEmbankment DamCan add own photo for your own projects.Concrete Inflow Channels
15Pond 10847 Can add own photo for your own projects. Proposed Pond AccessRe-build Existing EmbankmentCan add own photo for your own projects.Improve Existing Swale
16Pond 10876 Stormwater Management Dry Pond 7’ High Earth Embankment Dam Metal riser structure is not in compliance with current standardsStormwater Management Dry Pond7’ High Earth Embankment DamAdjacent to County RoadDoes not meet current SWM requirements to achieve any MS4 credit.Erosion at OutfallCan add own photo for your own projects.Facility is undersized for drainage area
17Pond 10876 Can add own photo for your own projects. Install Infiltration BasinRe-build EmbankmentCan add own photo for your own projects.Access from Dufief Mill Road
18Pond 10887 Stormwater Management Dry Pond Metal riser structure is not in compliance with current standardsStormwater Management Dry Pond10’ High Earth Embankment DamExisting Pedestrian Path Across EmbankmentDoes not meet current SWM requirements to achieve any MS4 credit.Concrete Channels Prevent Facility from Operating Properly per Current StandardsCan add own photo for your own projects.Access from Grey Colt Drive
19Pond 10887 Can add own photo for your own projects. Remove Existing Inlet/Outlet Structure and Provide Additional SWM TreatmentAccess from Grey Colt DriveCan add own photo for your own projects.Convert Downstream End of Facility to Wet PondRe-build Embankment
20Metal riser structure is not in compliance with current standards Pond 10891Metal riser structure is not in compliance with current standardsStormwater Management Dry Pond8’ High Earth Embankment DamDoes not meet current SWM requirements to achieve any MS4 credit.Available room for wet pond and potential bioretention terracesCan add own photo for your own projects.Concrete Channels Prevent Facility from Operating Properly per Current Standards
21Pond 10891 Can add own photo for your own projects. Potential for Terraced Bioretention along sides of facilityAccess from Appaloosa WayRe-build EmbankmentCan add own photo for your own projects.Convert Downstream End of Facility to Wet Pond
22Project Objectives - SWM All ponds - 24-hour detention for stream channel protectionPonds 10887, Permanent Wet PoolPond – Dry PondPond Convert to Infiltration area/Dry Pond CombinationPond – Install bioswale in-lieu of inlet/outlet structure at Northeast inflow point.Pond – Potential bioretention terracesCan add own photo for your own projects.
23Project Objectives - Streams Stream protectionModify outlet works to better regulate pond discharge and protect Rich Branch and Sandy BranchAchieve partial to full channel protection volume requirement (depending on pond)Can add own photo for your own projects.
24Project Objectives - Maintenance Replace existing risers with water-tight structuresInstall impervious liner on dam embankmentsInstall internal drain in downstream embankmentsCan add own photo for your own projects.
25Project Objectives - Aesthetics Landscape all facilities with native vegetation to improve aquatic habitat and aestheticsCan add own photo for your own projects.
26Project CostsFinancial – estimated cost of $2.3M financed through MCDEP CIP Program using funds generated through the Water Quality Protection ChargeRecreational – temporary construction impacts to pedestrian path on top of embankments at PondForest – tree clearing for to comply with state dam safety laws along the downstream toe of the dam.Traffic – construction traffic enter and exit roadways Monday – Friday, 7AM to 4PMNeighborhood – construction traffic and noise will typically occur Monday – Friday, 7AM to 4PMCan add own photo for your own projects.
27Project BenefitsWater – improved water quality and stream water temperature through better management of runoffEnvironmental – reduced downstream discharge allows for natural self-repair of stream channel. Increased aquatic and riparian habitat through landscaping and reforestation.Recreational – increased aesthetic appeal of pondsMaintenance – safer operating structure that will require minimal structural maintenance in future.Can add own photo for your own projects.
28Estimated Design and Permitting Timeline Design – September 2013 – March 2014Approvals – March/April 2014Permits – April 2014Bidding –May 2014Construction – June - August2014Can add own photo for your own projects.
29What to expect during construction DurationApproximately 3 monthsConstruction HoursMonday through Friday, 7AM – 4PMSafetyOpen sides of site will be fenced with orange construction safety fence to separate construction from residents.TrafficMinor impacts to traffic from entering and exiting construction traffic and contractor parking during the day.NoiseContractor is required to comply with Montgomery County Noise Ordinance – site elevation will help alleviate noise pollution.SedimentContractor will be required to comply with Montgomery County Sediment Control Permit and not track dirt onto roadsCan add own photo for your own projects.
30Questions? For more information: Doug Streaker, ,