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Howard Bend Levee District City of Maryland Heights, Missouri

December 27, 2006

howard bend stormwater management system and implementation guidelines

Howard Bend S to rmwate r Managemen t S y s t em & Imp lemen ta t i on Gu i de l i n e s 1

Table of Contents

Project Study Area and Planning Context ................2

Elements of Stormwater System ..........................4

Flood Storage and Discharge System..... ................7

Primary Collection System......... ..........................9

Trail Network.... ................................................15

Howard B end . C i t y o f Mary land He igh t s 2

PROJECT STUDY AREA AND PLANNING CONTEXT

Project Study Area

The Howard Bend Levee District (District) project area is a State of Missouri jurisdiction consisting of 8,600 acres located along the Missouri River. Most of the District lies within the City of Maryland Heights, while a small portion to the south lies within the City of Chesterfield. Due to its location in the 100-year floodplain and its inherent flooding potential, the land has generally been used for agricultural purposes. Recent improvements, such as a levee and a roadway interchange, have made the project area suitable for development.

A 500-year levee and seepage berm have been constructed to protect the site from major flood events along the Missouri River. In addition, an interchange has been constructed at the intersection of Maryland Heights Expressway and Page Avenue (Route 364). Future expansion of the Expressway is in the planning stages to extend it to the south beyond Page Avenue. In response, the City of Maryland Heights, in cooperation with the District, has undertaken a number of planning activities to enhance the area’s development potential.

The District is responsible for providing, or assuring, flood and stormwater protection within its boundaries. To meet these responsibilities and to further enhance the area’s development potential, a comprehensive stormwater conveyance and storage system is being developed to manage adjacent and local stormwater flows. Transportation and land use planning efforts are also underway for the entire project area and are discussed later in this document.

Planning Context

This document presents the framework and

implementation guidelines for the project area’s

stormwater conveyance and storage system. It builds

THE PROJECT STUDY AREA

upon preliminary engineering studies completed by

Horner & Shifrin, the District’s engineering consultant,

and on prior or current planning studies completed by

the City. The components of the stormwater system

have been developed to be multi-functional and to add

value to various development parcels and the District.

A key consideration is the manner in which the

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GOALThe stormwater system should be based on sound engineering practice. Objectives• Best Management Practices should represent

sound engineering practice.• Multi-functional uses, such as trails, parks, and

habitat should be developed where appropriate as ancillary uses that are ”layered” on to the systems primary function of stormwater management.

GOALThe stormwater system proposed should support the development goals of land owners and the City of Maryland Heights.Objectives• Proposals in the City’s 2002, and current, Howard

Bend future Land Use Plan recommendations should be incorporated.

• Specific goals and needs of land owners in the District should be considered.

GOALCreate value for property owners and the City through the design of an innovative stormwater system.Objectives• Concepts should be developed that optimize the

development potential of individual sites.• Concepts should be developed that illustrate how

stormwater can be incorporated into development as an amenity.

Goals and ObjectivesThe following goals and objectives were developed to guide the planning process.

PROJECT STUDY AREA AND PLANNING CONTEXT

stormwater conveyance system can help to shape and

reinforce desirable development patterns and become

a key part of the community’s parks and open space

network.

This plan was developed through a process that

included consultation and collaboration with property

owners, Levee District board members, development

consultants, and the District’s engineer. The District has

collaborated with the City of Maryland Heights staff,

their planning consultants, the planning commission,

and the public. The St. Louis County parks department

staff has been involved in planning work directly

related to trails and stormwater management proposals

that have a direct effect on Park properties.

GOALSupport local and regional plans for open space and trails.Objectives• Concepts should be developed that incorporate

the open space and trails plan proposals and goals of the City of Maryland Heights and St. Louis County.

• Concepts should incorporate proposals for regional trails proposed by the Great Rivers Greenway.

GOALDevelop a stormwater system that is based onenvironmentally sound practices and policies.Objectives• Proposals should facilitate enhancement and

establishment of the Page Avenue mitigation area.• Stormwater facilities that support a diverse aquatic

and riparian habitat should be developed.• Proposals that emphasize biotechnical, “soft”

engineering solutions should be emphasized where feasible.

• Facilities that support ecologically based methods for pest and invasive species control should be encouraged.


Elements of the Stormwater System

The proposed stormwater system is comprised of four

types of conveyance and storage. From largest to small-

est in scale, this system includes the following compo-

nents.

n River Flood Protection System (RFPS)The River Flood Protection System consists of the

500-year levee system, including flood walls, seepage

protection berms, and outlet gates. This system

has been completed by the District and has made

development feasible in the project area. Hence, this

document does not discuss this system.

n Flood Storage and Discharge System (FSDS)The Flood Storage and Discharge System consists of

Creve Coeur Creek, Fee Fee Creek, and Louiselle Creek;

the flank levees along the creeks; Creve Coeur Lake;

and, the gated outlet culvert through the 500-year levee

to the Missouri River. The Flood Storage and Discharge

System accommodates upland runoff as well as local

runoff and provides the outlet for all discharges to the

river.

ELEMENTS OF THE STORMWATER SYSTEM

STORMWATER PROTECTION SYSTEM DIAGRAMLocation of system components are diagrammatic. Final location to be determined as individual areas develop.


n Primary Collection System (PCS)This system collects runoff from several developing

parcels and conveys that stormwater to the flood stor-

age and discharge system. There are two subsets to the

system:

A) Outfall Primary Collection System (OPCS)This portion of the PCS is directly connected to the

FSDS and typically provides contiguous, connected

stormwater management for large parcels, or a

number of smaller parcels. Because it is contiguous

and connected, it can function as an integral part

of the regional open space and park uses proposed

for the FSDS. In addition to its primary stormwater

management functions, the PCS will also provide fill

material for adjacent development sites.

B) Shared Primary Collection System (SPCS)This portion includes localized outfalls that are entirely

within larger parcels or that serve as the interface be-

tween smaller parcels.

n On-Site Drainage System (ODS)The On-Site Drainage System includes site specific

solutions that serve individual development parcels in

the District and conveys resulting runoff to the Primary

Collection System or directly to the Flood Storage and

Discharge System, depending on the parcel location.


System-Wide Policies for Multiple Use

These general policies and guidelines are intended to apply to all components of the stormwater man-agement system. Policies and guidelines that apply to specific, individual elements of the system are described in the sections that follow.

Compliance and Compatibility with Regulations and Current Planning ContextPolicy #1: Improvements shall comply with all applicable MSD, State, and Federal standards and guidelines regarding stormwater management and water quality.

Policy #2: The Howard Bend District Storm Water Master Plan prepared by Horner and Shifrin constitutes the basis for policies and guidelines that integrate stormwater management systems with proposed development.

Policy #3: These policies and guidelines are compatible with, and will become an integral part of, land use and site planning recommendations prepared for the District by the City.

Policies Focused On Creating “Multiple Benefit” Stormwater SystemsPolicy #4: Runoff rates and volumes should be reduced to more closely match natural conditions. Increased runoff associated with development can be environmentally harmful, causing erosion in stream systems and generating greater pollutant loading downstream. A variety of techniques, including fragmenting and reducing impervious areas, and using landscape or other pervious areas to slow runoff and promote infiltration, should be incorporated into the system.



Policies Focused On Creating “Multiple Benefit” Stormwater Systems continued...

Policy #5: Stormwater quality management and flood control should be integrated within the system. Both stormwater quality treatment and flood control detention goals can be accomplished within the same land area through a coordinated design approach.

Policy #6: The District and the City should coordinate efforts to develop a “multiple use” stormwater system that simultaneously provides water quality treatment, recreational opportunities, and environmental responsibility. To maximize efficiency of land use and provide the greatest value, the system should exhibit, where appropriate, the following characteristics:

• Land areas included in the stormwater system should be made available to the public by the District and private land owners for a range of ac-tive and passive recreational uses, open space, and trails.

• Ecologically and biotechnically based engineering practices should form the basis for storm channel design. The system should be designed to maintain required levels of stormwater storage and treatment in a manner that allows for a reasonable level of biological diversity.

• The District should support and promote the creation of multi-functional facilities. For example, wildlife habitat should be created as part of storm-water management and water quality treatment facilities. Trails should function in dual roles as facility maintenance access roads where feasible.

Policy #6: Stormwater quality facilities that enhance the site, the community, and the environment, should be encouraged. Gardens, plazas, rooftops, and even parking lots can become amenities and provide visual interest while performing stormwater quality functions and reinforcing urban design goals. The

integration of water quality features and associated landforms, walls, landscape, and materials can reflect the standards and patterns of a neighborhood and help to create lively, safe, and pedestrian-oriented districts.

Policy #7: Stormwater quality needs should be considered early in the design process. When included in the initial planning for a project, opportunities to integrate stormwater quality facilities into a site can be fully realized.

Policy #8: The entire site should be considered when planning for stormwater quality treatment. Often, stormwater quality and flood detention are dealt with only at the low corner of the site and ignored on the remainder of the project. In this “end-of-pipe” approach, all the runoff volume is concentrated at one point and it can be difficult to fit the required detention into the space provided, necessitating the use of more costly mechanical systems.

Policy #9: Sustainable facilities that can be safely maintained should be key considerations in the design process. Stormwater quality facilities must be properly and consistently maintained to function effectively and ensure long-term viability and public acceptance of these facilities.

Policy #10: Facilities should be designed with public safety in mind. One of the highest priorities is to protect public health, safety, and welfare. Stormwater facilities must be designed and maintained in a manner that does not pose health or safety hazards to the public, with respect to public access or to mosquito/West Nile virus concerns. Structures required as part of the stormwater system will be designed to minimize vertical drop offs, avoiding the need for fencing, railings, and other typically employed barriers.


FLOOD STORAGE AND DISCHARGE SYSTEM

Flood Storage and Discharge System

Improvements to the creek flank levees have been

proposed to increase their capacity to store and convey

water into the Missouri River through the Flood Storage

and Discharge System area. To maximize develop-

ment value, improvements to the flank levees would

be designed to protect the area from flooding, creating

attractive and usable open spaces and maximizing open

space frontage for adjacent development parcels.

Terracing the bottom of the storage area allows greater

ecological and landscape diversity by providing for

more diverse riparian zones and wildlife habitats. The

higher elevations, emphasizing those areas least likely

to be flooded during a frequent storm event (five years

or less), could allow for paths and manicured turf areas.

The lower areas could allow for naturalized wildlife

habitats, groundwater recharge, and water-quality infil-

tration areas.

The figures on this page illustrate alternative levee

alignments or the water storage and conveyance area

along Creve Coeur Creek that accomplishes flood con-

trol, recreation, and habitat restoration objectives.

Levee edges that are planned in conjunction with the development planning for adjacent parcels can provide for the required stormwater storage.

Layout of the flank levees without consideration for the development potential of adjacent parcels, could limit its potential value as a flood storage and open space amenity.


FLOOD STORAGE AND DISCHARGE SYSTEM

Policies and Implementation Guidelines

n The District supports significant public access for active and/or passive recreation, and regional and local trails. The trails may be part of the levee District maintenance road access network, or may be independent of maintenance roads. Where appropriate, provision will be made for limited recreational uses on terraces above the five-year flood level.

n Stabilization of creeks will be accomplished primarily through biotechnical means.

n The development of storage capacity will incorporate off-channel wetland, riparian, and upland habitats. Water quality capture volumes from

Introduce sinuosity into the creek alignment to stabilize the banks

and to promote habitat diversity.

Terrace the storage area bottom to create meadows, wetlands,

and riparian areas. Diverse landscape types function as part of

a water quality treatment system and provide diverse wildlife

habitats.

Ponds

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adjacent parcels may be accommodated in this area to enhance wetland habitat potential.

n As appropriate, wetland banking areas will be incorporated for mitigation of off-site wetland impacts as part of the open space area.

n The levee alignments will be determined, to the degree possible, as an integral part of planning for the adjacent parcels to promote stronger connections between adjacent development and proposed open space uses of the area.

Manicured pocket parks above the five-year flood level.

Recreational and maintenance trails on top of the flank levee.

Buildings built into flank levee overlooking the open space.


PRIMARY COLLECTION SYSTEM

The Primary Collection System

ALTERNATIVE APPROACHES CONSIDERED

The Primary Collection System will have a profound

impact on the image, function, and development

potential of the area. Functional requirements

identified in the Horner & Shifrin plan were the basis

for evaluation of two alternative approaches for the

layout of the Primary Collection System.

Approaches considered include:

n Consolidated Storage, Conveyance, and TreatmentThis scenerio emphasizes a regional approach to storage

and water quality treatment. Consolidated stormwater

storage is available for those parcels that are adjacent

to, or close enough to convey water to, the Primary

Collection System.

n Dispersed on-site Storage and Conveyance and treatmentWith this approach, stormwater is treated and stored

on individual development sites. This approach results

in a highly dispersed system of detention and water

quality treatment.

PREFERRED ALTERNATIVEAn alternative relying primarily on consolidated

storage, conveyance, and treatment, supplemented

by on-site facilities, was selected as the preferred

alternative. With this approach, greater efficiency,

roughly a ten percent reduction in land area required

for storage is possible. Additionally, this approach

would utilize the Page Avenue mitigation area for

stormwater storage. With consolidated facilities,

THE PRIMARY COLLECTION SYSTEMThe primary collection system approach emphasizes the use of consolidated detention wherever possible to allow for more developable land within private parcels. The approach also allows for the development of a trail and open space network.

there is also a greater potential for the development of

recreational open space, trails, and habitat areas.

The development areas east and west of Page


Avenue present distinctly different opportunities for

incorporating the preferred approach.

DEVELOPMENT AREA EAST OF PAGE AVENUEA consolidated system in this area will be created

through the development of a parkway (referred to as

the River Valley Parkway) that integrates a collector

road with a regional stormwater conveyance, storage,

and treatment in the median. This corresponds to the

Outfall Primary Collection System shown in the overall

framework diagram on page 4. The Parkway supports

transportation planning recommendations for the

area through the development of a collector roadway

extending from the Riverport Business Park, over Page

Avenue, to River Valley Road. The Parkway provides

adjacent development with a more visible, identifiable

address, and creates a landscape setting that enhances

the value of adjacent parcels.

The alignment of secondary channels perpendicular to

the Parkway and to the Maryland Heights Expressway

allows for maximum exposure of future development

to the Parkway and the Expressway. The Secondary

Channels also provide for important cross connections

for local trails between the River levee regional trail

and trails within Creve Coeur Park. The outfall

channel along Creve Coeur Mill Road will allow for

the creation of an open space buffer between the Park

and anticipated loading and service areas for future

development along the Expressway. The buffer allows

for an important trail link between the Fee Fee Creek

corridor and Page Avenue trails.


DEVELOPMENT AREA WEST OF PAGE AVENUEStormwater requirements for the area west of Page

Avenue are considerably different than for the area to

the east. Because the area is constrained by the River

levee and the Page Avenue mitigation area, it forms a

long narrow series of parcels linked by River Valley

Road, paralleling the River levee. Stormwater must be

conveyed from the River levee in an easterly direction

to the Page Avenue mitigation area, which serves as the

area’s outfall.

There are two exceptions to this pattern at the south end

of the area. East of the Water Treatment Plant, portions

of the development area drain to a conveyance along

the edge of the bluff. The areas west and south of the

treatment plant drain directly into the River. East of

the plant, portions of the area drain into a small Shared

Primary Collection System that outfalls into the Page

Avenue mitigation area.

Because of the areas configuration, the stormwater

network is much more localized, lacking the hierarchy

that is characteristic of the area East of Page Avenue.

Because the mitigation area requires additional sources

of water to develop wetlands, only water quality

capture volumes will be required for developments in

the area east and north of the treatment plant. Larger

volumes may be conveyed into the mitigation area. As

parcels develop, owners will be required to construct

stormwater storage facilities in the mitigation area

that enhance the habitat of the area as part of the PCS

system. The PCS system south of the treatment plant

outfalling directly into the River must comply with the

Policies and Guidelines issued for the Development

Types described later in this document.




The biological viability and ecological diversity of the primary system is important system-wide, and principles and practices described elsewhere in this report should be uniformly adhered to. The importance of the primary systems visual qualities, and the opportunity for recreational use varies greatly depending on its location, and on the proposed land use. The following guidelines apply for different PCS channel types.

Outfall Primary Collection System (PCS)This portion of the PCS is directly connected to the Flood Storage and Discharge System. It provides a continuous, connected stormwater management system that can expand and enhance regional open space. • Publicly accessible multi-use and regional trails

should be accommodated where feasible as part of the stormwater system maintenance road network.

• Habitat areas, and localized passive parks, should be provided where feasible.

Shared Primary Collection System (SPCS)This portion of the PCS includes localized outfalls that convey stormwater from large parcels or serve as combined conveyances for smaller parcels to the PCS. This portion of the system will often be entirely within larger parcels, or will serve as the interface between smaller parcels. • A local and/or regional trail corridor should be

provided when designated on the District Trails Network plan.

• Private recreation and park facilities should be provided as appropriate.

Specific portions of the system vary greatly in impor-tance for their potential to support the enhancement of the image and open space qualities of the area. The relative importance of the channels is based on their visibility from major roadways such as the pro-posed River Valley Parkway, or the Maryland Heights

Expressway, or on their proximity to land use types where image is important, or where there are signifi-cant densities of residents, visitors, or workers.

The importance of the visual quality, aesthetics, and the multi-use potential of the conveyances are ranked high, medium, or low depending on the presence of the factors such as those described above. Of univer-sal importance is the need to maintain ecologically diverse and biologically healthy permanent ponds, if required or desired, to minimize the potential for mosquito habitat. A description of high, medium, and low importance areas follows.

High Importance• Conveyances adjacent to the proposed River Val-

ley Parkway, the Maryland Heights Expressway, and Page Avenue

• Conveyances along or adjacent to proposed internal roadways at the fronts of retail, office campus, mixed-use/retail/entertainment, and multi-family development types

• Conveyances within multi-family, office campus, and retail/mixed-use/entertainment areas where buildings front on the conveyances or where there are high concentrations of visitors or work-ers

Medium Importance• Conveyances along secondary circulation routes,

in parking areas, and along loading and service areas in multi-family, office campus, and retail/mixed-use/ entertainment development types

• Conveyances along the primary access routes for office/flex, office district/light industrial devel-opement types

Low Importance• Conveyances within or backing on to office

district/light industrial, office/flex developement type

• Conveyances along retail/mixed-use/entertain-ment loading and delivery areas


Outfall Primary Collection System (PCS) - River Valley Parkway


Shared Primary Collection System (SPCS)

Locate permanent pools at areas of flow concentration and limit pool size to minimize seasonal drying

Concentrate frequent storm flows to allow multiple use of channel bottom and to minimize mosquito breeding areas

Maximize storage/conveyance capacity while maintaining positive drainage on side slopes

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High Importance• Design roadway, conveyance and storage, and landscape/aesthetics as an

integrated whole.• Side slopes vary.• Integrate sediment traps into less visible landscape areas.• Limit permanent pool areas; provide lining as required to maintain

permanent water levels and avoid.seasonal. drying• Maintain channel/storage capacity

High Importance• Integrate design of conveyance and storage into project

and building entries; locate water quality treatment and frequently inundated areas on less visible portions of a site

• Maintain appropriate width/depth channel proportion to the greatest degree possible

Medium/Low Importance• Maintain appropriate side slopes in more visible areas

when possible• Integrate conveyance and detention into parking and

roadway landscape concepts

Low Importance• Not applicable

SLOPE

SLOPE

SECONDARY CHANNEL

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Medium/Low Importance• Not applicable


Outfall Collection System/Buffer Edge

graphic to be added


High Importance• Not applicable

Medium/Low Importance• Maintain slopes in more visible areas when possible• Provide for recreational trails – see trail diagram• Integrate retail/ commercial frontages and unite lots as

appropriate

Low Importance• Conveyance/storage not visible from adjacent public

roadways, retail frontage or side lots

Vary channel alignment where parcel inefficiences allow

Vary side slopes in highly visible areas

Locate ponding to enhance the identity and landscape qualities of adjacent buildings

Vary channel bottom to concentrate ponding areas and to promote varied ecology

Locate on-site BMPs to enhance habitat value of the PCS and to screen parking and service areas

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Longitudinal Section through Primary Collection System

Acceptable Geometry for “Dry” Channel

Acceptable Geometry for “Wet” Channel


CHANNEL FLOW



n Multiple use trails will comply with City and County trail design standards.

n The maximum distance between trail links connecting Creve Coeur Park and the River levee will be approximately 1 mile.

n All designated multiple use trails shown on the Trail Concept Plan will be made accessible to the general public.

TRAIL NETWORK

Trail Network

The area’s Primary Collection System plays an

important role in extending the City of Maryland

Heights and St. Louis County’s trail and open space

network. Equally important is the role of the Missouri

River levee in providing an important link in the

regional trail network being developed by Great Rivers

Greenway’s organization. The City’s long-term vision

for the area includes a trail network linked to the

County and regional systems. This hierarchy of trails

will provide an amenity for employees, residents, and

visitors of the area. It will allow for, and encourage,

bicycle commuting.

The accompanying Trail Concept Plan is intended to

illustrate the potential system. Specific trail corridor

alignments and locations are shown as minimum

implementation requirements, and will be determined

as more specific development plans for the area are

proposed.

TRAIL CONCEPT PLANProposed multi-use trail locations are diagrammatic. Final locations are to be determined as areas develop.


IMPLEMENTATION GUIDELINES FOR DIFFERENT DEVELOPMENT TYPES

On-Site Drainage System

The Howard Bend Future Land Use Plan describes

a mix of land uses that support the City’s goals for a

vibrant community in which to live, work, and enjoy

leisure-time activities. One of the most important goals

of this plan is to assure that the stormwater framework

reinforces the Land Use Plan’s vision for the community

to be developed in the Valley.

The Simplified Land Use Plan illustrated on this page

consolidates land use types described in detail in the

Future Land Use Plan. The land uses were grouped

according to similar building form, site plan, and

location requirements, and characteristics. For example,

office and light industrial are grouped together

because of similar building floor plate size, site plan

requirements and density of employees. Similarly, the

entertainment and regional retail land use types were

grouped together because of similar building types,

the type of visitor, and site plan and highway visibility

requirements.

Each development type offers specific opportunities

and constraints for the incorporation of the On-Site

Drainage System and Shared Primary Collection

System, and water quality treatment systems. Specific

implementation guidelines are provided for each of the

five major categories of development described above.

The last section of the document provides detailed fact

sheets on individual water quality Best Management

Practices (BMPs) and Implementation Details.SIMPLIFIED LAND USE PLAN

Documents

howard bend stormwater management system and ...mplakedistrict.com/wp-content/uploads/2016/05/... · regional trails proposed by the Great Rivers Greenway. GOAL Develop a stormwater