HomeMy WebLinkAboutFile Documents.110 Coach Rd.0159.2019 (2).ARBK STORMWATER BEST MANAGEMENT PRACTICES
OPERATIONS AND MAINTENANCE AGREEMENT
City of Aspen, Colorado
THIS AGREEMENT,made and entered into this 30 day of November ,2021 ,by and between(Insert
Full Name of Owner) Colter Van Dome l e n hereinafter called the
"Landowner",and the City of Aspen,Colorado,hereinafter called the "City".
WITNESSETH
WHEREAS,the Landowner is the owner of certain real property described as(Pitkin County tax Map/Parcel
Identification Number) 273502303007 located at
110 + 112 Coach Road, Aspen CO 81611 and as more fully as follows,to wit:
also known as, Lot 7 in Stage Road PUD ,hereinafter called the "Property";and
WHEREAS,the Landowner is proceeding to build on and develop the property;and
WHEREAS,the stormwater management BMP Operations and Maintenance Plan for the property identified herein
has been approved by the City,herein after called the"Plan",which is attached hereto as Appendix A and made part
hereof,as approved by the City,provides for management of stormwater within the confines of the Property through
the use of stormwater management or Best Management Practices(BMPs)facilities;and
WHEREAS,the City and the Landowner,its successors and assigns,agree that the health,safety,and welfare of
the residents of City of Aspen,Colorado and the maintenance of water quality require that on-site stormwater
management/BMP facilities be constructed and maintained on the Property;and
WHEREAS,the City requires,through implementation of the Plan from the Landowners dated
11—3 0—21 and attached hereto,that on-site stormwater management/BMPs as shown on the Plan be
adequately constructed,operated,and maintained by the Landowner,its successors and assigns.
NOW,THEREFORE,in consideration of the foregoing premises,the mutual covenants contained herein,
and the following terms and conditions,the parties hereto agree as follows:
1.Construction of BMP facility by Landowner.The on-site stormwater management/BMP facilities shall be
constructed by the Landowner,its successors and assigns,in accordance with the plans and specifications
approved by the City and identified in the Plan.
2.Duty of Operation and Maintenance of Facility.The Landowner,its successors and assigns,including any
homeowners association,shall adequately operate,inspect,and maintain the stormwater management/BMP
facilities as acceptable to the City and in accordance with the specific operation,inspection,and maintenance
requirements noted in the Plan. Adequate operation and maintenance is herein defined as good working condition
so that these facilities are performing their design functions.
3.Duty of Documentation. The Landowner,its successors and assigns,shall document inspections,maintenance,
and repairs performed and provide said documentation to the City or its representatives upon request.
4.Right of Entry on Property. The Landowner,its successors and assigns,hereby grant permission to the City,
its authorized agents and employees,to enter upon the Property at reasonable times and upon presentation of
proper identification,and to inspect the stormwater management/BMP facilities whenever the City deems
necessary.The purpose of inspection is to follow-up on suspected or reported deficiencies,to respond to citizen
complaints,and/or to assure safe and proper functioning of the facilities.The City shall provide the Landowner,
its successors and assigns,copies of the inspection findings and a directive with timeline to commence with the
repairs if necessary.
5.Failure to Maintain. In the event the Landowner,its successors and assigns,fails to construct,operate and
maintain the stormwater management/BMP facilities in good working condition acceptable to the City,the
City,its authorized agents and employees,may enter upon the Property and take whatever action(s)deemed
necessary to correct deficiencies identified in the inspection report and to charge the costs of such construction
or repairs to the Landowner.It is expressly understood and agreed that the City is under no obligation to install,
construct,or routinely maintain or repair said stormwater management/BMP facilities,and in no event shall this
Agreement be construed to impose any such obligation on the City.
6.Reimbursement by Landowner.In the event the City pursuant to this Agreement,performs work of any nature,
or expends any funds in performance of said work for labor,use of equipment,supplies,materials,and the like,
the Landowner,its successors or assigns,shall reimburse the City upon demand,within thirty(30)days of
receipt thereof for all actual costs incurred by the City hereunder.
7.Duty to Inspect by City.The City,its employees or representatives,shall inspect the stormwater
management/BMP facilities at a minimum of once every three years to ensure their continued and adequate
functioning.
8.Release of City. The Landowner,its executors,administrators,assigns,and other successors in interests,shall
release the City,its employees and designated representatives from all damages,accidents,casualties,
occurrences,or claims which might arise or be asserted against said City,employees,and representatives from
the construction,presence,existence,operative or maintenance of the stormwater management/BMP facilities
by the Landowner or City. In the event that a claim is asserted against the City,its elected officials,City
Officers or employees,the City shall promptly notify the Landowner and the Landowner shall defend,at its own
expense,any suit based on the claim. If any judgment or claims against the City's employees or designated
representatives shall be allowed,the Landowner shall pay all costs and expenses regarding said judgment or
claim.
9.Recording of Agreement running with the Property. This Agreement shall be recorded in the real property
records of Pitkin County,Colorado,and shall constitute a covenant running with the Property or land,and shall
be binding on the Landowner,its administrators,executors,assigns,heirs and any other successors in interests,
in perpetuity.
IN WITNESS WHEREOF the undersigned have hereunto affixed their signatures as of the date first above written.
LANDOWNER:
By:_ Print Name: Co(k e w e ten
State of Colorado) :ss
County of Pitkin)
The foregoing Agreement was acknowledged before me this 3 day of Qe -r-;20 2-I
by Co/1"- 4)-r aonta•e ft - •
CANDACE M.IHRlt;
NOTARY PUBLIC �}.7
STA1'B OF COLORADO ( Z
NOTARY ID 20214018280 Notary ublie
MY COMMISSION EXPIRES MAY 10,2025
My
May- t 0, 2 P
THE CITY OF ASPEN:
By:_ Print Name:
State of Colorado) :ss
County of Pitkin)
The foregoing Agreement was acknowledged before me this day of ,20 ,
by
Notary Public
My Commission Expires:
110 + 112 Coach Road
Lot 7 Stage Road PUD
STORMWATER MAINTENANCE PROCEDURES
Table of Contents 1
1.0 Introduction 2
1.1 Elements of a Maintenance Program 2-4
1.2 Facility Inspection & Maintenance 4-5
1.3 Description of Drainage Facilities and Special Maintenance Provisions .. 5
2.0 Grass Buffers and Swales as applicable 5-6
2.1 Inspection 6
2.2 Debris and Litter Removal 6
2.3 Aeration 6
2.4 Mowing 6-7
2.5 Irrigation Scheduling and Maintenance 7
2.6 Fertilizer, Herbicide, and Pesticide 7
2.7 Sediment Removal 7-8
2.8 Grass Buffers and Grass Swales Maintenance Checklist ..8-9
3.0 Underground BMPs 9
3.1 Inspection 9-10
3.2 Debris Removal 10
4.0 Maintenance Plan—Drywells 10
4.1 Inspection Schedule 10
4.2 Maintenance 11
5.0 Conveyance Storm Water Pipe 11-12
6.0 Glossary of Onsite Storm Water Terms. 12-13
7.0 References 14
Appendix:
Site Specific 1iMP's
Sample Stormwater Maintenance Plan(SMP) Inspection Log
Plan of Stormwater Facilities—Exhibit"A"and Exhibit"B"
1
110 + 112 Coach Road
Lot 7 Stage Road PUD
1.0 Introduction
In order for stormwater BMPs to be effective, proper maintenance is essential. Maintenance
includes both routinely scheduled activities, as well as non-routine repairs that may be required
after large storms, or as a result of other unforeseen conditions. BMP maintenance is the
responsibility of the BMP owner. In recent years,the impacts on area waterways,due to the urban
development projects, have altered drainage patterns, which can often result in flooding. Normal
day-to-day activities such as washing the car and fertilizing the lawn, have also
contributed to water pollution. Excess fertilizer, lawn chemicals, automotive products, pet waste,
leaves, debris, litter and anything else that washes from the landscape are carried with each rain
storm into drainage systems, some of which flow directly into area waterways. BMPs reduce the
flow which allows for filtration of pollutants before the stormwater enters streams, and rivers. To
ensure that BMPs perform as expected, they must be maintained properly.
Why BMPs Have been Designed in Concert with the Site Stormwater Plan
No two BMPs are alike, and their maintenance needs may differ widely. This section focuses on
maintenance of in-service BMPs and provides recommendations for ensuring proper
maintenance of private facilities.
Types of BMP used at this location:
Grassed Swales are gently sloped areas of vegetation that retard the flow of runoff, channeling it
to other BMPs. Grassed swales are typically found in residential developments as an alternative
to curb and gutter. Swale maintenance is typically the responsibility of the homeowner and
includes mowing and periodic reseeding. Mowing the grass too short or improperly applying lawn
chemicals can negatively impact the design performance of the BMP.
Filter Strips and Buffers are areas of vegetation that remove pollutants in runoff as the water
flows through it. Filter strips are similar to grass swales, only wider. Buffer areas are similar to
filter strips, but contain a variety of vegetation, including trees and shrubs.
Drywells are underground, vertical concrete pipe structures that dispose of excess stormwater
runoff by means of percolation with the added benefit of increasing stormwater water quality
prior to discharge into the local soil matrix.
1.1 Elements of a Maintenance Program
Overview of BMP Maintenance
BMPs will not perform as designed, if not regularly maintained. If a facility's storage capacity is
reduced, downstream flooding will indicate a problem; however, if a facility is not removing
2
110 + 112 Coach Road
Lot 7 Stage Road PUD
sediment and nutrients as designed, it will be difficult to know since these indicators are less
apparent. A regular maintenance program is the best way to ensure that a BMP will consistently
perform water quality improvement functions. It is important to realize that while general
maintenance tasks can be outlined, actual maintenance needs will vary according to specific site
conditions, particularly the in regards to following elements:
Landscaping: Certain vegetation may require more attention. Consider using native plants to
reduce maintenance needs.
Upstream Conditions: Watershed conditions upstream of the facility will affect the amount of
sediment and pollutants that must be managed.
Safety: Some tasks can be effectively handled by residents; however, a maintenance program
should ensure the safety of anyone carrying out tasks, and often a professional should be hired to
do the work.
Technical Expertise: BMPs are stormwater treatment facilities. While many maintenance needs
like litter and debris removal are obvious, others are less apparent.
Routine Maintenance Needs Inspections
Local regulations require a regular schedule of inspections. Annual inspection by a qualified
professional is recommended to ensure that the installed BMPs are functioning properly.
Vegetation Management
Vegetative cover serves several purposes in BMPs: First, it slows the velocity of the runoff and
filters sediment from runoff as it is collected in the BMP. Second, it prevents erosion of the banks
and bottom of the drainage channels and swales. Grass is generally used around retention basins,
infiltration trenches and in and around dry detention basins. It must be mowed and maintained.
Mowing requirements can be altered site specific needs and in concert with adjacent properties.
The grass in a BMP may be hardiest if maintained as an upland meadow, cutting no shorter than
6-8 inches. Maintaining a more manicured expanse of grass decreases the effectiveness of the
BMP, as well as, increasing maintenance costs. Wetland plants may also be
used along the fringe of the BMP in areas where conditions are favorable. However, some of these
types of plants may inhabit native plant species. The vegetation surrounding infiltration trenches
or buffer strips also removes sediment before the stormwater reenters the BMP. If plants are
damaged or become laden with sediment, they can no longer perform adequately.
Therefore, the condition of these areas should be closely monitored, and vegetation should be
replaced if necessary.
Debris and Litter Removal
Regular removal of debris and litter is efficient and effective and has the following benefits:
3
110 + 112 Coach Road
Lot 7 Stage Road PUD
-Reduces the chance of clogging in outlet structures, drywells, and other components.
- Prevents possible damage to vegetated areas.
- Reduces potential mosquito breeding habitats.
- Maintains facility appearance.
Mechanical Component Maintenance
Each type of BMP may have mechanical components that need periodic attention to ensure their
continued performance. Valves, gates, pumps, fences, locks and access hatches should be
maintained at all times. Design and site factors will determine the amount of maintenance that is
necessary.
Pest Control
Mosquito and other insect breeding grounds can be created by standing water. The most effective
control technique in retention basins is to prevent stagnant areas.Prompt removal of floating debris
is also helpful.
Non-Routine Maintenance Needs
Sediment Removal in Detention Basins
Sediment will accumulate in a BMP and will eventually need to be removed. Although different
facilities design requirements vary greatly, there are general recommendations on when the
removal shall be administered. Sediment removal is usually the largest single cost of BMP
maintenance.
1.2 Facility Inspection & Maintenance Procedure
Stormwater facilities play an important part in managing the stormwater that we receive annually
in Aspen. The term "stormwater facility" refers to any landscaped or structural feature that
collects, conveys, cleans or infiltrates runoff water. There are many types of stormwater facilities,
ranging from simple swales and ponds to more complicated filter systems and flow control devices.
On-site stormwater facilities work together to control runoff water, reduce flooding and prevent
pollution. Owners of single-family residential properties with privately-owned drainage and
stormwater facilities are required by the City of Aspen to maintain these
facilities and to establish standards for performing periodic inspections, and for performing any
maintenance identified.
Basic maintenance work may be performed by the owner or property manager, although some
tasks are best left to an experienced contractor.
4
110 + 112 Coach Road
Lot 7 Stage Road PUD
Step 1. Identify
The first step is facility identification, so you know what types of stormwater facilities you
have. Look on the site plan of your property (see Appendix), and note the main facility types
indicated(such as drywells), along with related drainage components (such as downspout
pipes and culvert pipes). Locate the various facilities on the ground. Note that most drainage
systems consist of components for four main purposes: stormwater collection (such as
downspout pipes), conveyance (e.g. culvert pipes and swales), water quality treatment (e.g.
drywells) and flow control (via infiltration and/or surface discharge).
To assist you in identifying components, refer to the definitions and illustrations on the pages
that follow.
Step 2. Inspect
For all facility components that you have identified, conduct an inspection. You may conduct
the inspection yourself via the use of a property manager or contractor. Refer to the following
Stormwater Facility Maintenance Checklist, which describes the maintenance standards for
each component,identify defects, and formulate a plan for their remedy. For each facility,note
on the Inspection & Maintenance Checklist the condition of the facility (good, fair or poor),
and any problems or other observations.
Step 3. Maintain
For all facility components, if the inspection indicates maintenance is needed; have the work
performed by competent personnel. Basic maintenance tasks may be performed by the
property owner(s) or property manager, but difficult or potentially dangerous tasks should be
performed by an experienced professional. Use caution when inspecting and working on or
near facilities, and stay out of confined spaces such as catch basins, manholes, and drywells.
Note the action taken and the date, and record this information on the Log Sheet. Mark the
check boxes on the Inspection& Maintenance Checklist corresponding to the maintenance
accomplished on each facility.
1.3 Description of Drainage Facilities and Special Maintenance Provisions
Project specific maintenance provisions have been summarized for this maintenance facility as
part of the Appendix.
2.0 Grass Buffers and Swales
Grass buffers and swales require maintenance of the turf cover and repair of rill or gully
development. Healthy vegetation can often be maintained without using fertilizers because
5
110 + 112 Coach Road
Lot 7 Stage Road PUD
runoff from lawns and other areas contains the needed nutrients. Periodically inspecting the
vegetation over the first few years will help to identify emerging problems and help to plan for
long-term restorative maintenance needs. The following section presents a summary of specific
maintenance requirements and suggested frequency of action.
2.1 Inspection
Inspect vegetation at least twice annually for uniform cover and traffic impacts. Check for
sediment accumulation and rill and gully development.
2.2 Debris and Litter Removal
Remove litter and debris to prevent rill and gully development from preferential flow paths around
accumulated debris, to enhance aesthetics, and prevent floatables from being washed offsite. This
should be done as needed based on inspection, but no less than two times per year.
2.3 Aeration
Aerating manicured grass will supply the soil and roots with air. It reduces soil compaction and
helps control thatch while helping water move into the root zone. Aeration is done by punching
holes in the ground using an aerator with hollow punches that pull the soil cores or "plugs" from
the ground.Holes should be at least 2 inches deep and no more than 4 inches apart.Aeration should
be performed at least once per year when the ground is not frozen. Water the turf thoroughly,prior
to aeration. Mark sprinkler heads and shallow utilities such as irrigation lines and cable TV lines
to ensure those lines will not be damaged. Avoid aerating in extremely hot and dry conditions.
Heavy traffic areas may require aeration more frequently.
2.4 Mowing
When starting from seed, mow native/drought-tolerant grasses only when required to deter seeds
during the first three years. Following this period,mowing of native/drought tolerant grass may be
reduced to maintain a length of no less than six inches. Mowing of manicured grasses may vary
from as frequently as weekly during the summer and no mowing during the winter. The two most
important facets of mowing are mowing height and frequency. The minimum height for any lawn
is 2 inches. The preferred mowing height for all Colorado species is 2.5 to 3 inches. Mowing to
less than 2 inches can result in decreased drought and heat tolerance and higher incidence of
insects, diseases and weeds. Mow the lawn at the same height all year. There is no reason to mow
the turf shorter in late fall. Mow the turf often enough so no more than 1/3 of the grass height is
removed at any single mowing. If your mowing height is 2 inches, mow the grass when it is 3
inches tall. You may have to mow a bluegrass or fescue lawn every three to four
days during the spring when it is actively growing but only once every seven to 10 days when
growth is slowed by heat, drought or cold. If weather or another factor prevents mowing at the
6
110 + 112 Coach Road
Lot 7 Stage Road PUD
proper time,raise the height of the mower temporarily to avoid cutting too much at one time. Cut
the grass again a few days later at the normal mowing height.
2.5 Irrigation Scheduling and Maintenance
Adjust irrigation schedules throughout the growing season to provide the proper irrigation
application rate to maintain healthy vegetation. Less irrigation is typically needed in early summer
and fall, with more irrigation needed during July and August. Native grass should not require
irrigation after establishment, except during prolonged dry periods when supplemental,temporary
irrigation may aid in maintaining healthy vegetative cover. Check for broken sprinkler heads and
repair them, as needed. Do not overwater. Signs of overwatering and/or broken sprinkler heads
may include soggy areas and unevenly distributed areas of lush growth. Completely drain and
blowout the irrigation system before the first winter freeze each year. Upon reactivation of the
irrigation system in the spring, inspect all components and replace damaged parts, as needed.
2.6 Fertilizer, Herbicide, and Pesticide Application
Use the minimum amount of biodegradable nontoxic fertilizers and herbicides needed to establish
and maintain dense vegetation cover that is reasonably free of weeds. Fertilizer application may
be significantly reduced or eliminated by the use of mulch-mowers, as opposed to bagging and
removing clippings. To keep clippings out of receiving waters, maintain a 25-foot buffer adjacent
to open water areas where clippings are bagged. Hand-pull the weeds in areas where weed
problems are apparent.
Frequency of fertilizer, herbicide, and pesticide application should be on an as-needed basis only
and should decrease following establishment of vegetation.
2.7 Sediment Removal
Sediment removal should be on an as needed basis, based on periodic inspections. Frequency
depends on site-specific conditions. For planning purposes, it can be estimated that 3 to 10% of
the swale length or buffer interface length will require sediment removal on an annual basis.
For Grass Buffers: Using a shovel,remove sediment at the interface between the impervious area
and buffer.
For Grass Swales: Remove accumulated sediment near culverts and in channels to maintain flow
capacity. Replace the grassy areas as necessary. Reseed and/or patch damaged areas in
buffer areas, side slopes, and/or channel locations to maintain healthy vegetative cover. This
should be conducted as needed based on inspection. Over time, and depending on pollutant loads,
a portion of the buffer or swale may need to be rehabilitated due to sediment deposition. Periodic
7
110 + 112 Coach Road
Lot 7 Stage Road PUD
sediment removal will reduce the frequency of revegetation required. Expect to replace turf in the
buffer interface area every 10 to 20 years.
2.8 Grass Buffers and Grass Swales Maintenance Checklist
Grass buffers and swales require general maintenance of the turf grass cover and repair of any rill or
gully development. Healthy vegetation can generally be maintained without using fertilizers because
runoff from lawns and other areas contains the needed nutrients. Occasionally inspecting the
vegetation over the first few years will help to determine if any problems are developing and to plan
for long-term restorative maintenance needs. The following presents a summary of specific
maintenance requirements and a suggested frequency of action for Grass Buffers and Grass Swales:
Required Action Maintenance Objective Frequency of Action
Mowing Maintain irrigated turf grass Routine—As needed to
at a recommended height of 2 maintain grass height or
to 4 inches tall. Non-irrigated based on inspection. Will
native grass should be vary from as frequently as
maintained at 6 to 8 inches weekly during the summer,
tall. to no mowing during the
winter.
Fertilizer, Herbicide and Use the minimum amount of Routine—On an as-needed
Pesticide Application biodegradable, nontoxic basis only.
fertilizers and herbicides
needed to maintain dense
vegetation cover that is
reasonably free of weeds.
Hand pulling of weeds is
preferred in areas with
limited weed problems.
Irrigation Adjust irrigation throughout Routine—Adjust and
the growing season to maintain throughout growing
provide the proper irrigation season.
application rate to maintain
healthy vegetation. Less
irrigation is typically needed
in early summer and fall,
with more irrigation needed
8
110 + 112 Coach Road
Lot 7 Stage Road PUD
during July and August.
Check for broken sprinkler
heads and repair them, as
needed. Do not overwater.
Signs of overwatering and/or
broken sprinkler heads may
include soggy areas and
unevenly distributed areas of
lush growth.
Reseeding/Vegetation Reseed and/or patch Routine—As needed by
Replacement damaged areas in buffer, side inspection. Expect turf
slopes and/or channel to replacement for buffer strips
maintain healthy vegetative once every 5 to 15 years.
cover.
Litter and Debris Removal Remove litter and debris to Routine—As needed by
prevent gully development, inspection,but no less than
enhance aesthetics, and two times per year.
prevent floatables from being
washed offsite.
3.0 Underground BMPs
3.1 Inspection
Maintenance Checklists
The checklists in this guide are for you to use when inspecting and maintaining the stormwater
facilities on your property. If you are missing a particular checklist, or if you have additional
facilities not identified or addressed in this guide, please contact your site developer, design
engineer, or local jurisdiction.
The checklists are in table format for ease of use. Each checklist tells you what part of the feature
to check,how often, and what to check for, as well as, the recommended remedies available. Log
sheets are included to help you keep track of when you last surveyed the storm drainage system.
The following tools are recommended during the course of performing maintenance procedures:
- Gloves.
-A flashlight(to inspect outlet structures, catch basins, manholes or pipes).
9
110 + 112 Coach Road
Lot 7 Stage Road PUD
-A long pole or broom handle (see below).
- Some kind of pry bar or lifting tool for pulling manhole and grate covers.
- Standard yard tools, such as a rake and a shovel
- Tape measure or yardstick
Due to OSHA regulations,you should never stick your head or any part of your body into a
manhole or other type of confined space. When looking into a manhole, drywell, or catch
basin, stand above it and use the flashlight to help you see. Use a pole or broom handle that
is long enough when you are checking sediment depths in confined spaces. Always properly
replace grates and lids.
All Underground BMP Treatment Devices:
Because subsurface treatment devices are normally located below the ground surface, they tend to
be —out-of-site, out-of-mind. Therefore, they often do not receive regular maintenance, nor is
their performance periodically monitored. The following outlines maintenance requirements for
Subsurface Treatment Devices including underground Sand Filter Vaults.
Inspect underground BMPs at least quarterly for the first two years of operation and then twice a
year for the life of the BMP, if a reduced inspection schedule is warranted based on the initial two
years. Specifically look for debris that could cause the structure to bypass water quality flows.
Strong odors may also indicate that the facility is not draining properly. Inspection should be
performed by a person who is familiar with the operation and configuration of the BMP.
Inlets, Catch Basins and Outlet Structures
Inspect inlets, catch basins and outlet structures frequently; at a minimum, inspect after every
storm event exceeding 0.6 inches. Removal of flow blocking debris is critical for flood control.
3.2 Debris Removal
All Underground BMPs: Follow the manufacturer's recommended maintenance requirements
and remove any flow blocking debris as soon as possible following inspection.
4.0 Maintenance Plan -Drywells
4.1 Inspection Schedule
Drywells must be inspected and maintained quarterly to remove sediment and debris that has washed into them.A maintenance
plan shall be submitted to the City in the Drainage Report describing the maintenance schedule that will be undertaken by the
owners of the new residence or building.Minimum inspection and maintenance requirements include the following:
•Inspect drywells at least four times a year and after every storm exceeding 0.5 inches.
•Dispose of sediment,debris/trash,and any other waste material removed from a drywell at suitable disposal sites and in
compliance with local,state,and federal waste regulations.
•Routinely evaluate the drain-down time of the drywell to ensure the maximum time of 24 hours is not being exceeded.If
drain-down times are exceeding the maximum,drain the drywell via pumping and clean out the percolation area(the
percolation barrel may be jetted to remove sediment accumulated in perforations.If slow drainage persists,the system may
need to be replaced.
•Inspect the 6-inch perforated pipe to ensure the surrounding filter fabric has not become clogged.
10
110 + 112 Coach Road
Lot 7 Stage Road PUD
4.2 Maintenance
Disposal of debris, trash, sediment, and other waste material removed from a drywell should be
done at suitable disposal/recycling sites and in compliance with local, state, and federal waste
regulations.
Routinely evaluate the drain-down time of the drywell to ensure the maximum time of 24 hours is
not being exceeded. If drain-down times are exceeding the maximum, drain the drywell via
pumping and clean out the percolation area (the percolation barrel may be jetted to remove
sediment accumulated in perforations). If slow drainage persists, the screened rock in the bottom
may need to be replaced.
5.0 Conveyance Storm Water Pipe
Storm water piping conveys storm water in, through, and out of storm water facilities. Pipes are
built from many materials and are sometimes perforated to allow storm water to infiltrate into the
ground. Storm water pipes are cleaned to remove sediment or blockages when problems are
identified. Storm water pipes must be clear of obstructions and breaks to prevent localized
flooding. All storm water pipes should be in proper working order and should be maintained as
listed and checked every two years.
Conveyance Storm Pipe
Potential Conditions When Recommended Maintenance Procedures
Maintenance is
Defect Needed
Root enters or
Obstructions, deforms Use mechanical methods to remove root.
Including pipe, reducing flow. Do not put root-dissolving chemicals in storm
Roots piping. If necessary, remove the vegetation
over the line.
Sediment& Sediment depth Access pipe via open ends,pipe termination points
Debris is greater than 20% or cleanouts and remove sediment by mechanical
of pipe diameter. means or jetting.
11
110 + 112 Coach Road
Lot 7 Stage Road PUD
6.0 Glossar' of Onsite Storms ater Terms
Best Management Practices (BMPs) — Structural features or procedures that reduce the adverse
impacts of development on the quantity and/or quality of runoff water.
Buffer—The zone along a sensitive aquatic area that provides protection,stability, shading, slope
and hank stabilization, and input of organic debris and coarse sediments to streams. It
allows room for aCt tion in aquatic system boundaries, attenuation of surface water flows,habitat
for wildlife, and protection from disturbance or intrusion by humans or domestic animals.
Catch Basin —An inlet box set into the ground, usually rectangular and made of concrete, capped
with a grate that allows stormwater to enter. A sump in the bottom catches sediment.
Conveyance — A mechanism or device for transporting water, including gutters, pipes, channels
(natural or man-made), culverts, manholes, etc.
Drainage S'stem A combination of facilities for the collection, conveyance, containment,
treatment, discharge and/or disposal of stormwater runoff.
Dry Pond—Casual name for an Infiltration Basin, a detention facility that drains completely after
a storm. This type of pond has a pipe outlet at the bottom.
Easement — A legal encumbrance placed against a property's title to reserve access. Drainage
easements typically provide access to pipes and/or ponds, and are generally 15 to 20 feet wide.
Infiltration — The soaking of water through the soil surface into the ground (percolation is
essentially the same thing). Many ponds arc designed to infiltrate or retain storm water, and thus
do not have a regularly used discharge pipe.
Infiltration Facility (or Structure) — A facility (pond or trench) which retains and percolates
storm water into the ground, having no discharge (to any surface water) under normal operating
conditions.
Manhole—A larger version of the catch basin,often a cylindrical concrete structure with a circular
solid lid. Manholes allow access to buried pipes(such as storm sewers) for maintenance.
Permeable Concrete Pavers - A layer of concrete pavers separated by joints filled with small
stones with a base and subbase that allow the movement of stormwater through the surface.
12
110 + 112 Coach Road
Lot 7 Stage Road PUD
Runoff — The portion of water originating as precipitation that becomes surface flow. See
"stormwater"below.
Sand Filter — A treatment facility that removes pollutants and sediments from stormwater by
percolating stormwater through a layer of sand. Clean water exits the bottom of the facility through
a pipe or by infiltration.
Drywell-A drywell is a subsurface storage facility that receives and temporarily stores storm water
runoff from roofs of structures. Discharge of this stored runoff from a drywell occurs through infiltration
into the surrounding soils. Typically, drywells are subsurface, structural concrete chambers that are
accessible via a removable cast iron cover.
Stormwater— The portion of precipitation that falls on property and that does not naturally
percolate into the ground or evaporate, but flows via overland flow, interflow, pipes or other
features into a defined surface water body or a constructed infiltration facility.
Swale—A shallow surface drainage conveyance with relatively gentle side slopes, generally with
flow depths less than 1 foot. Essentially a broad, flat-bottomed ditch.
8.0 References
Sources:
City of Aspen URMP - Chapter 6 BMP Maintenance
November 2010 Urban Drainage and Flood Control District 6-7
Urban Storm Drainage Criteria Manual Volume 3
Stormwater Quality BMP Implementation Guidelines City and County of Denver, Colorado
13
Appendix
14
SITE SPECIFIC BMPS'S
1. Inlets, Catch Basins and Underground Piping:
Various inlet structures including Trench Drains and Catch Basins as well as Underground
Piping have been installed to intercept storm water on the site and route it to detention area.
Pipe located on the site includes mostly 4" and 6" PVC. Refer to full size as-built for the
locations of these facilities for maintenance in accordance with Sections 3.0, 5.0 and 6.
2. Underground Drywell:
An underground water quality drywell has been installed adjacent to the maintenance
facility to intercept storm water from the roof downspouts and area drains. The drywell is
composed of structural concrete and has a top and middle access lid. Each lid provides a
means to access the drywell to perform required maintenance. Maintenance for the
drywells should be in accordance with applicable portions of Section 4.0 "Underground
BMP's"listed above and in Section 4.0"Maintenance Plan—Drywells". (See Exhibit"B"
for location).
15
Sample Storm Water Maintenance Plan (SMP)
Inspection log
Inspector Name City of Aspen
Inspection Date Address
Date Date Date
Inspection Inspection Frequency Maintenance Items Checked Maintenance Maintenance Observations&Remarks
Due Performed Completed
1 Storm water System
2 Foundation Drain
Drywellw
3 4"Downspout Piping
Collection Piping
4 4"Drain Pipe
5 Trench Drain
6 Catch Basins