Green Infrastructure Retrofit Planning for MS4 Stormwater

Green Infrastructure Retrofit Planning for MS4 Stormwater

Program Coordinators David Kubek, CPESC/CPSWQ

Senior Planner CNY Regional Planning & Development Board

Introduction to green infrastructure as a water resources management tool

Planning for green infrastructure retrofits Special retrofitting considerations Inspection and maintenance guidelines Funding of green infrastructure construction

and maintenance Maintenance responsibility and access issues Examples and case studies

PROGRAM OUTLINE

Reduction in initial stormwater runoff – Less water to deal with!

Storage and uptake of stormwater near source – Volume control

Pollutant removal = water quality improvement Uses:

– Stormwater treatment – Combined Sewer Overflow (CSO) abatement – Correction of sanitary sewer inflow/infiltration

WATER RESOURCES BENEFITS OF GREEN INFRASTRUCTURE

OTHER BENEFITS OF GREEN INFRASTRUCTURE

Community aesthetics and quality of life

NYS Stormwater Management Design Manual, 2010

Air quality improvement

Energy savings

Mitigation of urban heat island effect Water

conservation

Carbon sequestration

Habitat

Education

Source: Onondaga County Save the Rain Program


Source: Roofscapes Inc. www.roofmeadow.com

http://savetherain.us/wp-content/uploads/2011/11/GIF-CNY-Jazz-Arts-Foundation-photo1.jpg

HOW CAN GREEN INFRASTRUCTURE BE USED TO SOLVE STORMWATER PROBLEMS?

Keep water out of the sewer system Delay flow into the system Remove runoff through plant evapotranspiration Pollutant treatment Caution: It’s not always the

– Entire solution – Only solution – Best solution!

But: – It’s often a key part of the solution!

Not for control of large storms/volumes

Source: City of Seattle Public Works

Source: Low Impact Development Center, Inc.

Municipalities are required to “consider using green infrastructure practices” in “routine upgrades to existing drainage systems”

– Retrofits may be requested as part of redevelopment projects

HOW IS GREEN INFRASTRUCTURE USED TO COMPLY WITH THE MS4 PERMIT?

– Common examples include:

• Converting closed systems to open drainage

• Introducing curb cuts and sunken vegetated islands

• Replacing old surfacing with pervious materials




PROGRAM OUTLINE

Scoping Desktop analysis and preliminary watershed

analysis Field reconnaissance investigation Compile retrofit inventory Revised watershed analysis Evaluation and ranking Preliminary design

RETROFIT PLANNING STEPS

Install on public land (includes demonstration projects)

Encourage onsite neighborhood retrofits

Bundle into municipal construction projects

Subsidized mitigation retrofits on private land

Require stormwater retrofits on redevelopment projects

Source: Center for Watershed Protection

RETROFIT DELIVERY METHODS

DEFINE PROBLEM SITE AND DRAINAGE AREA

Where is the… – Water quality impairment? – Flooding/drainage problem? – Sanitary sewer overflow? – Combined sewer overflow? – Algal bloom? – Sediment deposit? …etc.

From what area

of the landscape does the issue originate?

Where could a solution be physically located?

Retrofits New Construction Construction costs are 1.5 to 4 times greater

Designers seek least costly options

Requires significant data collection Much of the data may be borrowed from past designs

Assessment and design costs are higher Focus on low cost design and construction

Sized to meet subwatershed restoration objectives (or best one can do)

Sized to meet local stormwater design standards

Typically installed on public land Installed at new development projects

Urban soils often cannot support infiltration

Soils may support infiltration

Fingerprinted around existing development and infrastructure

More flexibility on where to locate practices on the site

Source: Center for Watershed Protection Urban Stormwater Retrofit Manual, 2007

RETROFITS VS. NEW CONSTRUCTION

Retrofits New Construction Must be acceptable to adjacent neighbors and landowners

Aesthetics are not always a major design factor

Most are publicly maintained and the public expects that they will be

Many require private maintenance, which is not frequently performed

Not all candidate sites are feasible Nearly all sites are made to work

Often tied into existing stormwater conveyance system

Usually creates the new stormwater conveyance system

Integrated with other restoration practices

Stand-alone practice

Public investment in watershed infrastructure

Private investment in stormwater infrastructure

Site visit is prerequisite for design Design may occur without site visit

Source: Center for Watershed Protection Urban Stormwater Retrofit Manual, 2007

RETROFITS VS. NEW CONSTRUCTION

RETROFIT SCOPING Tasks:

– Define the core retrofitting objective

– Review past, current and future stormwater management

– Translate objectives into minimum retrofit treatment performance criteria

– Define preferred methods of stormwater treatment

– Estimate retrofitting effort needed in the subwatershed

Source: Center for Watershed Protection 2007

Examples of retrofit objectives: – Correct past stormwater management mistakes – Reduce inflow to sanitary or combined sewers – Reduce future flood damage – Reduce loading of nutrients or other pollutants – Create wetlands and/or wildlife habitat – Recharge groundwater – Reduce bank erosion – Support downstream repairs

RETROFIT SCOPING

RETROFIT SCOPING

Review past, current and future stormwater management – Is the retrofit objective to correct a problem with an

existing practice?

– Are other practices in the watershed failing to address the issue?

• Maintenance lacking?

• Improper design?

– Have the existing practices ever functioned properly?

– Is new development planned in the subwatershed?

RETROFIT SCOPING

Treatment performance criteria – Minimum total area or area of impervious surface

treated?

– Targeted percentage or other measure of pollutant removed?

– Minimum water quality volume storage?

– Peak flow or volume control (e.g. channel protection volume)? (Caution)

– Volume of runoff reduction as part of a larger watershed effort

RETROFIT SCOPING

Define preferred methods of treatment – What practices work well in meeting the

objective? – What practices are likely to deliver the needed

performance criteria?

Estimate retrofit effort needed in subwatershed – Multiple practices/locations needed to meet

objective?

RETROFIT SCOPING

Flood control/large volume control – Stormwater ponds – Stormwater wetlands – Infiltration basins

Runoff reduction – Bioretention, rain gardens, cisterns, porous

pavement, vegetated swales, etc. – Almost any green infrastructure practice can

contribute

RETROFIT SCOPING

P removal (total P) – Bioretention (dissolved P) – Porous pavement (total P) – Media filter (total P and orthophosphate) – Stormwater retention ponds and wetland basins

(all P forms) N removal

– Filtration practices (bioretention, media filters) – Stormwater retention ponds and wetland basins – Grassed filter strips

Based on International Stormwater BMP Database, 2012

RETROFIT SCOPING

Sediment control/TSS removal – Bioretention, porous pavement, stormwater

ponds shown to have highest removals – Most practices provide significant benefits

Bacteria/pathogens – Retention ponds – Media filters Based on International Stormwater BMP Database, 2012

DESKTOP ANALYSIS

Check topography to locate low spots and verify drainage patterns

Use GIS, aerial photos to spot possible retrofit sites – Existing dry ponds and swales – Parking lots and other large areas of impervious ground – Parks and open spaces – Wide street rights-of-way – Open areas above culverts

Examine property ownership – Note public and vacant lands

Prepare maps for field investigation

FIELD RECONNAISSANCE

Identify opportunities

– Public visibility for demonstration project? – Aesthetic enhancements? – Energy, habitat, other auxiliary benefits?

Identify constraints – Groundwater table or bedrock? – Property ownership? – Access (construction,

maintenance)? – Conflicts with utilities, trees? – Hydraulic or grading concerns? – Pollutant hot spots?

PLANNING FOR GREEN INFRASTRUCTURE RETROFITS

CNY RPDB Green Infrastructure Planning Grant – American Recovery & Reinvestment Act funds

– Identified 104 sites in Syracuse Urbanized Area with water quality or quantity control issues

– 33 sites had good potential for use of green infrastructure or other stormwater retrofits

– Concept sketches with identified practices developed for 10 of these sites

DRAINAGE AREA MAPPING

Municipalities provided data where available: – Sewershed and system mapping data – Post-construction stormwater management

practice inventories

A GIS database was compiled Approximate drainage

areas affecting each site were delineated using available data and Digital Elevation Mapping

DETERMINE RUNOFF VOLUME AND POLLUTANT LOADS

– Pollutant amounts (e.g. phosphorus, sediment,

pathogens)

– Volume of stormwater

– Impervious surface coverage

Using land use, land cover, soils data, aerial photography, determine:

GIS POLLUTANT LOADING ANALYSIS

Simple Method analysis for each drainage area done using land use, land cover, and soils data – Impervious area coverage – Runoff volume – Phosphorus load

• Total and per acre – Total Suspended Solids load

• Total and per acre – Hydrologic Soil Groups

Observations made about possible factors contributing to water quality and quantity issues

GIS SUITABILITY ANALYSIS

A suitability analysis was completed in GIS – The analysis evaluated 6 factors that affect the

suitability of various practices: • Hydrologic soil group - are soils good for

infiltrating water? • Slope – high, low, or good range? • Land use • Proximity to roads • Proximity to wetlands • Presence of floodplains


A suitability analysis was completed in GIS – For each practice, factors were given a ranking

of 0 to 5 depending on how they affect viability • 5 = favorable to use • 0 = inhibits use

– These factors were weighted relative to their importance

– Total suitability score calculated – Once developed, matrix can be applied wherever

data exist

Result is a raster coverage with a total suitability value of 0 to 30 for each cell


Individual factors can also be displayed

DETERMINE PRACTICE TYPE AND LOCATION

Additional meetings were held for a total of 10 sites (Level 3)

Site visits to document: – Drainage patterns

– Existing drainage infrastructure

– Existing utilities

– Other site data

Specific practices and their approximate locations were discussed and determined

DETERMINE PRACTICE TYPE AND LOCATION

CONCEPT DEVELOPMENT

Concept sketches prepared showing possible configurations of proposed practices

– Not intended for final design!

– Includes:

Necessary drainage improvements

Existing structures

Locations of identified constraints

– Landscaping plans also developed for some projects

DEVELOP CONCEPTUAL DESIGN SKETCH

LESSONS LEARNED

Rarely possible to solve a large problem with a single retrofit at one location

– Often use multiple small-scale green infrastructure practices in the drainage area

More difficult to meet standards with retrofits than with new development

– Doing whatever is possible is a bit of a risk, but often something is better than nothing

A little creativity goes a long way on difficult sites




PROGRAM OUTLINE

Location – Best on sites with relatively flat slopes, but need some grade

to convey flow

– Groundwater separation needed for dry swales

– Existing drainage channels often under-capacity

Pretreatment – sediment forebay or pea gravel spreader

Drop structures or check dams can be used to create ponding cells

Can store snow, but need salt-tolerant vegetation

Cost: $20,000 to $60,000 per acre of impervious surface per Center for Watershed Protection (CWP), 2007

RETROFITTING CONSIDERATIONS: SWALES

Location

– Best on sites with slopes of 1 to 5 %

– Groundwater separation of 3 ft minimum

Pretreatment – use grass filter strip, pea gravel diaphragm, or two-cell design

Soil conditions determine if underdrain needed

Can store snow, but need salt-tolerant vegetation

Size – at least 5 to 10 % of contributing drainage area

Cost: $20,000 to $40,000 per impervious acre (CWP, 2007)

RETROFITTING CONSIDERATIONS: BIORETENTION


Location – As far as possible from trees

• Falling leaves

• Rodents and bird waste = contamination

Port hole required for access (inspection/maintenance)

Sizing

– One inch of runoff from 1000 sq. ft. of roof = 83 cubic feet

Cost: approximately $15 per gallon of storage

– May vary depending on treatment, plumbing retrofits, etc.

RETROFITTING CONSIDERATIONS: CISTERNS

Source: Center for Watershed Protection, 2007

Sizing

– Area 20% to 30% of roof area draining to it (1-inch rain)

Cost: $3 to $5 per cubic foot of runoff treated (CWP, 2007)

RETROFITTING CONSIDERATIONS: RAIN GARDENS

Location – Most effective in neighborhoods with

lot sizes ¼ acre or greater

– Locate a minimum of 10 feet away from foundation

– Well-drained soils preferred – otherwise need underdrain/soil amendments

– Cannot receive “hot spot” drainage

RETROFITTING CONSIDERATIONS: STORMWATER PLANTERS

Contained stormwater planter

Flow-through stormwater planter

Infiltration stormwater planter

Source: NYS Stormwater Management Design Manual, 2010

Location – At grade level or above ground – Infiltration planters – minimum 10 feet from building

foundations

Sizing – Store ½ inch of runoff above planter bed – Planting media – infiltration rate at least 2 in/hr

Overflow pipe – discharge runoff when ponding depth is exceeded – Waterproofing and dewatering


RETROFITTING CONSIDERATIONS: STORMWATER PLANTERS

Location – Soils must support adequate infiltration 0.5 – 3 in/hr

(check for grading, filling, compaction, disturbance)

– 3 feet above high water table

– Bottom of stone reservoir must be completely flat

– No hotspot runoff


RETROFITTING CONSIDERATIONS: PERMEABLE PAVEMENT

Source: Center for Watershed Protection, 2007


Backup water removal mechanism – Overflow edge – trench surrounding paver area, connect to

underlying stone reservoir

Overflow mechanism – bypass larger flows – Set storm drain inlets slightly above surface elevation

Sand or choker stone below reservoir to prevent flow paths from forming in underlying soil

Drainage area must be fully stabilized before construction

RETROFITTING CONSIDERATIONS: PERMEABLE PAVEMENT

Design options: – Extensive - thinner soil layer and are lighter, less

expensive and generally require low maintenance – Intensive - deeper soil layer, greater weight, higher cost,

increased plant diversity and maintenance needs Sizing based on:

– Soil medium volume – Pore storage – Evapotranspiration rate

RETROFITTING CONSIDERATIONS: GREEN ROOFS

RETROFITTING CONSIDERATIONS: GREEN ROOFS

Structural integrity – Many existing roofs can support

extensive system retrofits

– Intensive designs usually need reinforcement

Use existing downspouts if possible for excess runoff

Cost (CWP, 2007) – Extensive: $140 to $300 per cubic

ft runoff treated

– Intensive: $300 to $420 per cubic ft runoff treated


What’s a “subsurface gravel wetland”? – Not in NYSDEC Stormwater Management Design Manual

– retrofits only!

– Univ. of New Hampshire Stormwater Center design specifications

– Originally used for wastewater treatment – Best use: where no water quality treatment currently exists

RETROFITTING CONSIDERATIONS: GRAVEL WETLANDS

Source: University of New Hampshire Stormwater Center, 2007

– Horizontal flow-through treatment cells with pretreatment forebay

– Subsurface, microbe-rich, anaerobic ¾-inch stone substrate (saturated)

– Perforated risers

– Surface area covered by wetland soil and vegetated


Source: University of New Hampshire Stormwater Center (Roseen, Ballestro and Houle 2009)

Location

– May be an option for direct retrofit into failing or pre-2003 stormwater ponds, particularly dry detention

– Wet ponds need to be converted to dry ponds to support

– No permanent pool, but can support temporary channel protection volume storage (need separate cell for higher flows!)

– Low hydraulic head needed

– Soils must be low permeability or liner must be installed

Sizing

– Two-cell design recommended

– Water quality volume retained above substrate (10% in forebay)

Cost: $22,300 per acre of impervious treated (Houle, 2009)


Underground Injection Control (UIC) is an EPA regulatory program to prevent groundwater contamination

A practice is a Class V Underground Injection Well if it:

– Is a storm water collection system that relies on infiltration to collect and dispose of storm water runoff AND

– Discharges to the subsurface AND

– Consists of a hole or shaft that is deeper than it is wide, a subsurface distribution system, or an improved sinkhole

If above criteria are met, the practice is subject to requirements discussed at: http://water.epa.gov/type/groundwater/uic/class5/types_stormwater.cfm

SPECIAL RETROFITTING CONSIDERATIONS: INFILTRATION AND UIC REGULATIONS

Vegetation damage and mortality – Snow pileup

– Salt and deicers

Frost-freeze impacts on porous or permeable pavement – Frost heaving beneath pavers

– Freezing within aggregate pores

Underdrains should be oversized and extend below frost line

Overflow bypass design is critical

Rain barrels/cisterns - disconnect or winterize

SPECIAL RETROFITTING CONSIDERATIONS: COLD CLIMATE

Overflow bypasses

– Inline systems

• Systems with underdrains

• Force water to flow through

• Overflow not controlled

– Offline systems

• Contain a “flow splitter” device

• Excess water is diverted to another structure after capacity is reached

SPECIAL RETROFITTING CONSIDERATIONS

– Design underdrains to be cleaned out

• If ponding lingers in practices with underdrains, maintenance is needed

– Valves to open and close the systems

– Observation ports for water levels


Underdrain techniques and issues – Know characteristics of the native soil

– Ensure surrounding infrastructure is protected

• Basements, roads, parking

• Use liners as appropriate

Soil management techniques and issues

– Test infiltration rate (during design), don’t assume it

– Protect native soil during construction

• Limit access, grading and clearing

• Separate stockpiling if disturbance is necessary

– Isolate areas of contaminated soils


Soil management techniques and issues (ctd.) – Increase soil capacity by connecting planting areas

• Allows for sharing of root space

– Structural soil use • Addition of stone to improve load-bearing capacity of soil

– Avoid conflicts between rooting and infrastructure subgrade

• Place soil-free aggregate under hardscape areas

• Use root barriers

– Soil restoration – complete where needed!


Source: Cornell University Horticultural Program, 1995




PROGRAM OUTLINE

Tree Planting and Tree Pits

– Native, non-invasive species recommended

– Urban soils may require amendment and decompaction

– Mulch, water, and protect young trees

– Periodically check trees for damage and disease; prune or treat as necessary

– Replace dead trees

MAINTENANCE OF GI PRACTICES

Rain Gardens – Typically maintained by homeowners

unless on commercial property – education is critical

– Remove sediment accumulations or heavy organic matter

– Maintenance includes • Regular weeding

• Watering during dry times

• Replacing plants as needed

– Rain gardens should dewater within a few hours after rainfall


Stormwater Planters – Upkeep of plants and soil

medium

– Inspect after major storm events

– Remove accumulated debris and sediment buildup regularly

– Replace dead or dying vegetation

– Erosion repair, particularly at leader outflow points


• Replacement of vegetation with desired

plants

• Neglect of vegetation and soil maintenance

• Outright removal of the practice for other

landscaping


Rain gardens and stormwater planters

– Maintenance challenges and issues

• Removal of downspout connection to practice


Rain Barrels and Cisterns

– Inspect roof catchments to ensure that particulate matter is not clogging system

– Inspect/repair/replace: • Inflow, outflow, and overflow

pipes

• Diverts and cleanout plugs

• Screens and covers

• Accessories such as connectors or pumps


Rain Barrels and Cisterns

– Maintenance issues:

• Barrels/cisterns not emptied and are allowed to overflow

• Lack of maintenance leads to malfunction and failure

• Removal if not wanted and/or thought to be temporary

• Must be either properly insulated or disconnected during winter


http://www.lid-stormwater.net/raincist/raincist_benefits.htm

Green Roofs

– Inspect membrane, check for leaks, repair damage to or failure of waterproofing

– Watering, fertilizing and weeding especially as plants are becoming established

– Dead plants should be replaced

– Roof drains should be cleared when soil substrate, vegetation or debris clog the drain inlet


Green roof challenges and issues

– Insufficient maintenance and replacement of vegetation

• Weeds take over

• Soil medium erodes

– Improper or unsuitable vegetation

installed

– Building modifications reduce treatment area




http://savetherain.us/wp-content/uploads/2011/11/ElephantExhibit-Green-Roof.jpg

Permeable Pavement – Ensure paving area is free of debris and

clean of sediments; vacuum sweep at least 3 times/year

– Ensure pavement dewaters between storms (adequate drawdown 24 – 48 hrs.)

– Seed/stabilize bare soil spots in upland and adjacent vegetated areas

– Inspect for and repair deterioration and spalling

MAINTENANCE OF GI PRACTICES http://www.wbdg.org/design/lidtech.php


Permeable Pavement – Challenges and issues

• Accumulated sediment not removed regularly

• Modification for utility installation or other improvements

• Structural damage not repaired as needed

• Heavy traffic allowed on surfaces intended for light traffic

• Replacement with conventional pavement or treatment with sealer


Soil Restoration – Add 3 inches compost over

subsoil

– Till compost into subsoil using a plow-mounted disc or tiller

– Rock-pick until uplifted stones 4 inches and larger are removed

– Apply 6 inches topsoil

– Maintenance issues • Owner activities compact soil

• Vegetation intended to maintain soil structure is removed


Vegetated Swales – Requirements

• Maintain 4 to 6 inches of dense vegetation

• Remove sediment or debris buildup by hand in the bottom of the channel

• Inspect for standing water

• Restore design grade as necessary

• Repair rills in channel with compacted topsoil anchored by fabric; seed/mulch

– Maintenance errors • Excessive mowing

• Erosion allowed to occur with no stabilization

• Underdrain cleanout not performed


Bioretention – Maintain vegetation and replace plants as needed

– Remove weeds

– Maintain surface cover layer

– Address sediment clogging using core aeration, deep tilling, or replacement of

surface cover layer

– Inspect and clean inlets and pretreatment structures


Bioretention maintenance errors and issues

– Neglect of vegetation and weeding

– Replacement of vegetation with desired plants

– Outright removal of the practice for other landscaping

– Soil medium and/or underdrain allowed to clog, leading to excessive ponding and possible mosquito breeding


Photo by Don Stribick, Erie County SWCD

Subsurface gravel wetlands – Clean forebay of sediment when 10% full

– Remove trapped debris and sediment accumulation

– Mow/trim wetland vegetation (regular)

– Harvest wetland vegetation (every 1 to 3 years)

– Inspect vegetation health, density, diversity (after major storms in first year, then twice annually)

– Maintain 85% vegetative cover

– Check structural components for integrity

– Check for evidence of erosion and repair as necessary





PROGRAM OUTLINE

Town Drainage Districts – Under Town Law, benefitted properties can be

assessed for use of drainage facilities • Special District • Must benefit all properties within district and all

benefited properties must be included • Advantage – benefits of a few not paid for by all

residents

– Costs for district isolated on a separate assessment roll

FUNDING GREEN INFRASTRUCTURE RETROFITS

Town Drainage Districts - formation – Upon initiative of Town Board without petition

(subject to referendum) • Risk that owners will later not want district and vote it

down by referendum • Would leave town with unfunded dedicated improvements

– By petition of owners of at least half of assessed value in the district

• Difficult to obtain buy-in of lot owners after subdivided • Easy if all land is owned by single entity (i.e. prior to

subdivision approval)


County Drainage Districts – County has authority to create a drainage

district that benefits more than one municipality • Areas need not be contiguous as long as they are

interdependent • Administrative unit of county government • Charge based on benefit or assessed value

– Advantage in addressing multi-municipal, regional, and watershed-level issues


Town Drainage Improvements – Instead of a district, Town can provide

construction and maintenance of drainage improvements serving • The entire Town • A specified area

– Cost not borne solely by benefited properties – Non-benefited properties may perceive as

inequitable


Local Improvements – General City and Village Law authorize assessment

of benefited properties for local improvements • Service or improvement must enhance value of

benefited properties – Funded by

• Special assessments or • A combination of special assessments and general

fund (where authorized)


Drainage districts – benefits of consolidation – Reduces duplicative administrative needs resulting

from multiple districts – Allows greater flexibility in the use of funds for

projects throughout the district – Simplifies process for drainage district coverage of

new developments

Disadvantages – Some systems more expensive to operate than

others - consolidation could result in inequities


Benefits of watershed-based drainage districts – Allows funding to be dedicated to specific

improvements needed for water quality and quantity control in respective watersheds

– Justifies additional tax levies for water quality improvements affecting impaired waters

– Most appropriate for watersheds with additional requirements (e.g. Onondaga Lake) or identified problems


Impact fees – No enacting legislation, but not precluded by

law • CAUTION - May be subject to legal challenge if

construed as a tax rather than a fee!

– Purpose of fee must be directly related to mitigation of development’s impacts

– Fee must be in proportion to the actual monetary impact of the development (i.e. on the drainage or stormwater management system)


Impact fees (ctd.) – Would be charged on new developments that

impact existing offsite drainage system only

– Possible applications:

• Offset cost of building new infrastructure (capital expense only, not maintenance)

• Charge when 100% RRv can’t be met?

• Offset land use changes in impaired watersheds?

– Requires a Drainage Master Plan


Capital recovery fee – Charge to developer in lieu of constructing

stormwater management practices – Similar concept to impact fee (same cautions!) – Need to amend local law to implement!

• Developer must comply with NYS performance standards

• MS4 must ensure construction meets NYS requirements

• Performance-based standard must therefore exceed NYS minimum requirements to provide incentive


Reverse auction with private property owners as bidders – Municipality offers to provide rain barrels, rain

gardens, etc. to bidders

– “Purchases” treatment benefits from owners (as much as possible for given amount of $)

– Lowest bidders receive preference


Source: U.S. EPA

NYS Environmental Facilities Corporation – Green Innovation Grants Program (GIGP) – Funds construction of green infrastructure

projects that are on the IUP (Intended Use Plan) list for wastewater treatment

– Funds engineering design of green infrastructure volume control projects for which there exist: • Feasibility studies • Conceptual designs


Clean Water State Revolving Fund – Funds construction of projects under two

categories of regulatory programs: • Permitted facilities – MS4s are regulated under

SPDES as point sources - considered Publicly Owned Treatment Works

• Non-permitted facilities – If facility is not required by a SPDES permit, must be consistent with State Nonpoint Source Management Plan

– Capital costs only (not operation and maintenance) • Broad definition


Debt Financing – General obligation bonds (backed by taxation

or other income – considered strong credit) – Revenue bonds (backed by anticipated revenue

from a specific funded project – less applicable) – Advantage: allows distribution of expenses for

capital improvements over a time period of several years

– Disadvantages: voter referendum needed, accumulated interest


Banking/credit trading – Municipality could “purchase” credits from private

developers • Use excess stormwater treatment to fulfill Onondaga

Lake TMDL phosphorus reduction requirements

– Formal program with NYSDEC approval and oversight must be established

• Offsite “mitigation” must be at a 2 to 1 ratio relative to onsite requirement

• Purchase must occur in same watershed as offset


Stormwater utility (*No enacting legislation in New York State, not attempted *) – Distinct charge on property owners for use of the

stormwater drainage system – Parcel-based billing system - often uses a surrogate

for the amount of runoff generated, such as: • Impervious area

• Parcel size or zoning

– Proceeds would be used to fund retrofits and other stormwater program components

– Green infrastructure incentive – utility fee reduction





PROGRAM OUTLINE

Maintenance responsibility –The party responsible for

maintenance must be determined

• Individual property owner • Homeowners’ Association • Municipality

–Enforcement provisions may be • Contained in municipality’s local law • Part of a maintenance agreement and/or

deed restriction

MAINTENANCE AND ACCESS ISSUES

Maintenance responsibility (ctd.) –Responsible party must be educated on the

purpose and maintenance needs of the practice • Signage (required by permit)

• Outreach materials • Education by “word of mouth”


Source: City of Portland, OR

Pros and cons of private maintenance –Advantages

• Less costly (private or HOA funds used) • May be able to rely on property owner for

inspections –Disadvantages

• More difficult to control/enforce – contingency necessary in the event owner fails to maintain

• Ownership changes may create complications • Covenant running with the land must be

recorded in deed to enable intervention by MS4


Pros and cons of maintenance by municipality –Advantages

• Not reliant on changeable homeowner association or private owner

• Special enforcement actions not necessary • Lesser need for education?

–Disadvantages • More expensive, greater administrative burden • Need to establish easements on private property • Need to establish drainage district


CNY Stormwater Coalition Model Maintenance Agreement (commercial property owners) – Owner responsible for all routine maintenance work

– Owner has inspections of facilities performed by a qualified inspector

– Report submitted by June 30 of each year – if not done, municipality can complete inspection itself and notify owner of findings

– If identified issues are unresolved within 30 days of report, municipality may perform work itself - assess cost as tax lien

– Permission granted to access property

– Covenant running with the land

MAINTENANCE AGREEMENT

CNY Stormwater Coalition Model Maintenance Agreement (GI practices on residential properties) – Owner or successors/assigns responsible for all routine

maintenance work

– Municipality inspects facilities and notifies owner of findings

– Owner required to rectify any identified problems

– If identified maintenance issues are unresolved within 30 days of report, municipality may perform work itself and assess cost as tax lien

– Permission granted to access property (permanent easement recorded with deed), but notice provided to owner prior to entry

MAINTENANCE AGREEMENT




PROGRAM OUTLINE

Village of Lake George Beach Road – Cooperative effort between Lake George

Association, Warren County Highway, NYSDOT and FHA

– Rare example of use of porous asphalt on high-volume roadway

– Will remove silt, road salt, and nutrients from runoff and reduce ponding

– Protect recreational and drinking water uses of lake

RETROFIT EXAMPLES

“Save the Rain” – Onondaga County – Developed as an alternative to using exclusively

“grey” infrastructure to abate CSOs in Onondaga Lake Watershed

– Driven by Amended Consent Judgment and Onondaga Lake TMDL

– Over 80 projects completed or in progress in City of Syracuse

– Expanded to suburbs to address sanitary sewer inflow and infiltration issues in County sanitary district

RETROFIT EXAMPLES

Onondaga County “Save the Rain” - Otisco Street, Syracuse – Residential “green streets” project

RETROFIT EXAMPLES

– Curb extensions with curb cuts directing runoff to bioretention areas between new and existing curbs

– Runoff reduction of 2.25 million gallons/year

– Traffic calming benefits

Harbor Brook Treatment Wetlands Pilot – Onondaga County “Save the Rain” Program – Retrofit of Velasko Road detention basin – Side-by-side comparison of three types of

wetlands for CSO treatment • Floating wetland • Vertical flow wetland • Surface flow wetland

RETROFIT EXAMPLES

Save the Rain - Leavenworth/Barker Park – Perimeter of park surrounded with vegetated

swales atop stone infiltration beds in right-of-way • Stormwater captured from 5 adjacent streets

– Rain garden and porous asphalt basketball court also included

RETROFIT EXAMPLES

Save the Rain – Petit Library – “Green Library Initiative” – partnership between

Save the Rain and Onondaga Co. Public Library

RETROFIT EXAMPLES

– Porous concrete installed in part of existing parking lot

– Remainder of impervious drains to this area

– Subsurface stone infiltration basins to capture overflow Source: Onondaga County Save the Rain Program

Save the Rain – W. Genesee/N. Clinton Pocket Park – Retrofit of existing impervious lot to vegetated

park

RETROFIT EXAMPLES

– Stormwater planters define boundary of park, receive runoff from streets

– Tree planting and benches also added


Lenexa, Kansas “Rain to Recreation” – Rapidly developing suburb – Integrated Stormwater and Watershed

Management Master Plan • Based on updated Comprehensive Plan

– Correct existing problems in developed areas

RETROFIT EXAMPLES

Source: U.S. EPA, 2010 – New facilities to minimize runoff

– Protect undeveloped lands

Lenexa, Kansas “Rain to Recreation” – Water quantity control problems addressed

through large capital improvement projects – Purchases land in priority areas to provide:

• Flood mitigation • Stream protection • Water quality improvement • Recreational amenities

RETROFIT EXAMPLES

Source: U.S. EPA, 2010

RETROFIT EXAMPLES

Lenexa, Kansas – “Rain to Recreation” Funding – Small sales tax to support building

stormwater facilities – Stormwater utility for sustainable funding – Systems Development Charge –

• Requires new developers to pay “in-lieu” fee to recover costs for capital improvements

• City manages water quantity from new impervious surfaces

RETROFIT EXAMPLES

Emeryville, California – Declining industrial city ripe

for redevelopment – Developed comprehensive

set of stormwater policies and guidelines adapted to unique conditions • Minimize impervious area • Include vegetative

stormwater controls • Addressed lifespan of

practice



RETROFIT EXAMPLES

Emeryville, California – Significant challenges to use of green

infrastructure (limited infiltration opportunities) • High water table – risk to groundwater • Dense development patterns • Predominance of clay soils • Compaction and contamination of soils

– Two main strategies to address challenges • Reduce parking space quantity based on demand • Infiltrate, evapotranspire, and harvest/reuse

rainwater while adapting to space constraints

RETROFIT EXAMPLES

Greenwood Lake, New York – Village is an MS4 subject to

retrofit requirements under a phosphorus TMDL • Village Hall – impervious

parking lot replaced with permeable pavers

• “Green screen” • Rain gardens/vegetated swales • Pocket park was created

– Addresses a seasonal flooding problem in center of Village

Photos by Orange County Soil & Water Conservation District

RETROFIT EXAMPLES

Hempstead, New York – Averill Park

Source: American Society of Landscape Architects, www.asla.org

– Recreational ballfield with nuisance wet conditions and collapsed drainage system

– Drainage reconfigured to collect and detain flow in a wet meadow/bioswale area

– Neighboring playing field surface raised

– Groundwater recharge achieved onsite

– Used as educational demonstration re: stormwater wetlands

http://www.asla.org/

RETROFIT EXAMPLES

Miller’s Creek, Ann Arbor, Michigan – Implemented by Huron River Watershed Council – Utilized small BMPs and public education campaign to

restore habitat and biota of Miller’s Creek – Converted road stub to rain garden – Distributed rain barrels and removed downspouts – Enhanced existing stormwater pond – Neighboring property owners encouraged to

implement practices

Source: Huron River Watershed Council, http://www.hrwc.org/millerscreek

RETROFIT EXAMPLES

Mt. Airy Rain Catchers - Shepherd’s Creek, Cincinnati, Ohio

– Began with a demonstration project, information mailed to homeowners

– “Reverse auction” pilot project by EPA – Homeowners submit bids with amount they wish

to be paid for installation of rain gardens and/or rain barrels on their property • Lowest bidders most likely to be selected • Most bids were below $200

– EPA contractors performed maintenance • Only very basic O&M requested of residents

QUESTIONS AND DISCUSSION

David Kubek, CPESC/CPSWQ

Senior Planner

Central New York Regional Planning & Development Board

(315) 422-8276 x211

[email protected]

Documents

Green Infrastructure Retrofit Planning for MS4 Stormwater