Living with Water

The traditional ways of approaching stormwater management aren’t working in many places today. Part of this is due to environmental changes associated with more intense and more frequent storms that overwhelm the capacity of current drainage infrastructure. This is also due to development patterns associated with increases in surfaces that don’t absorb water and increases in building in floodplains and other flood-prone areas. Both of these trends decrease the storage capacity of the landscape by reducing the space for water to sit until it evaporates or absorbs into the ground. When traditional systems fail, communities flood. Living with Water means turning drainage from an annoyance to an amenity by creating space for stormwater in the landscape.

To increase resilience, many communities are transforming the way they approach stormwater management. Traditional approaches sought to convey water out of urban areas as fast as possible. New approaches, known as green stormwater infrastructure, encourage replicating the water cycle to manage rain where it falls. In some places, this means restoring natural systems or waterways that have been replaced or disrupted by human infrastructure. Other solutions use a combination of water-loving plants, porous soils, and landscaping to store water in place until it evaporates or absorbs. These strategies are paired with existing drainage infrastructure to increase stormwater storage capacity and to decrease pressure on existing systems.

Following the 2016 flood, Baker residents identified 22 goals in their recovery planning process. These included “implementing an effective stormwater management system” and “beautifying and upgrading public and private land.” Utilizing green stormwater infrastructure techniques in Baker can help residents achieve both goals. It can also improve wellbeing by increasing opportunities for residents to interact with and be in nature.

Strategies

Green Stormwater Infrastructure

The term green stormwater infrastructure describes a variety of methods that can be used together or separately to provide stormwater drainage and retention for lots, streets, communities, or regions in an ecologically responsible way. A common element of these methods is the use of natural systems to store water in place. Many strategies use specific plants and trees to absorb and clean stormwater. Others use permeable materials. This section shows a non-exhaustive list of green stormwater infrastructure strategies.

gray stormwater infrastructure

Gray stormwater infrastructure refers to concrete structures and systems designed to collect and transport rainwater. Traditional stormwater management systems use culverts, storm drains, and underground pipes to move rainwater away from streets, homes, and businesses as quickly as possible.

green stormwater infrastructure

Green stormwater infrastructure manages stormwater where it falls through mimicking or restoring natural water systems. Many strategies use soils, plantlife, or permeable surfaces to store and filter stormwater to improve water quality while reducing nuisance flooding.

Green Stormwater Infrastructure Complements Gray Stormwater Infrastructure

Green stormwater infrastructure is not a replacement for gray stormwater infrastructure systems. Green stormwater infrastructure is designed to work alongside gray stormwater infrastructure to decrease the negative environmental effects of gray stormwater infrastructure while providing greater capacity for storm water drainage and retention.

Green stormwater infrastructure reduces pressure on traditional drainage systems by storing water in the landscape. Credit: New Orleans Water Plan, Wagner & Ball.

Green Stormwater Infrastucture Design, Liberty High, Baton Rouge, LA. Credit: Reich Landscape Architecture

Stormwater Lots

This strategy transforms vacant residential lots into rain gardens or floodable parks. Stormwater lots store water and use native plants and specific soils to filter out pollutants and absorb rainwater, which improves water quality and decreases the amount of stormwater drainage systems must convey.

Part of the difficulty in implementing green infrastructure practices in densely developed areas is finding the space to make changes in a static built environment. One way around this dilemma is the conversion of vacant lots into Stormwater Lots. These are vacant or abandoned lots that have had debris and paved surfaces removed and vegetation and trees added to deliver economic, social, and environmental benefits. Zoning ordinance requires that “stormwater management” become an acceptable primary use in all or certain districts. Further, strategies for the development of these lots in concert with other efforts such as a bike/ped network or planned unit development is key to their success.

Stormwater Lot, New Orleans, LA. Credit: Dana Brown & Associates

Benefits and Considerations

Ecosystem Services

People receive many benefits from living in harmony with their natural environments. These benefits are known as ecosystem services. Sustainable development keeps ecosystems intact while promoting resilient growth. Green infrastructure enhances ecosystems by increasing plant life and natural environments, which in turn adds additional benefits for community members. For example, the native plants used in green infrastructure clean storm water run-off which improves water quality in the community.

ecosystem

An ecosystem is made of the living and nonliving elements that coexist in an area. This includes plants, animals, soils, land, water, and weather

S E C I V R E S M E T S Y S O C E

S E C I V R E S G N I T R O P P U S

FOOD

FRESHWATER

CLIMATE REGULATION

FLOOD REGULATION AND WATER PURIFICATIONSPIRITUAL/AESTHETICRECREATIONAL WATER SECURITY AND SANITATIONFOOD SECURITY LIVELIHOODS AND ENTERPRISE

SUFFICIENT NUTRITIOUS FOOD

HEALTH

SAFETY FROM HAZARDS SOCIAL COHESIONECONOMIC DEVELOPMENT OPPORTUNITIES

© IUCN WATER 2012

4 Ecosystems provide many services necessary for human wellbeing.

H U M A N

W E L L B E I N G

Cost Effectiveness

Green Infrastructure is cost effective because it works to provide long-term, environmentally sustainable solutions to problems that gray infrastructure has had a difficult time resolving. Once green infrastructure takes root, it implies less in terms of large-scale maintenance costs. It also provides places for native plants and animals to flourish, letting natural beauty shine through design and engineering solutions. Health benefits of human scale green infrastructure are noticeable and are directly produced by providing spaces that encourage physical activity and connecting with nature. Health benefits are also indirectly produced by designing spaces that can reduce flooding and the psychological strain that it causes residents. Providing infrastructure that boosts wellbeing is cost effective as well, because healthy citizens are better able to participate in society.

Maintenance Needs

Like all infrastructure systems, green infrastructure requires maintenance to function properly. However, the approach to its maintenance shows a stronger connection between ecologically responsible engineering and landscaping than has been seen in past forms of infrastructure. Maintenance needs are specific to each green infrastructure method. Some methods, like rain gardens, may require learning how to care for native plants and animals. The Environmental Protection Agency (EPA) provides free resources to support the proper maintenance of green stormwater infrastructure, including inspection checklists for porous pavements and bio retention systems, charts detailing the upkeep of vegetation and drainage systems, and proposed remedies to issues that may arise.

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Living with Water in Baker

D

B B D

B

A

B C Many different green stormwater infrastructure strategies to reduce flood risk can be used in residential subdivisions, like Baker Estates. As shown in the image, bioswales can be installed between streets and sidewalks to hold stormwater and beautify the neighborhood. Vacant lots can be converted into stormwater lots, which function as large rain gardens or floodable parks, to hold water during storms. Streets, sidewalks, and walking paths can be constructed with permeable pavement to enable rainwater to soak into the ground.

Toolkit

A. Bioswales

B. Rain Gardens

C. Permeable Pavement

D. Street Trees

Living with Water Toolkit

Maintaining quality of life and encouraging new investment in Baker requires coordinated strategies that reduce long-term risk. In the wake of the 2016 flooding, Baker has recognized the importance of traditional gray infrastructure and drainageways as necessary safety measures, However, there are currently few strategies that target water runoff where it is generated, slowing water flow, and reducing the need for more expensive infrastructure investment in the future. Through this process, Baker has recognized that there are new and innovative ways to introduce water into the landscape to reduce risk, increase economic vitality, and improve quality of life. The following provides a roadmap for policies that Baker may adopt to achieve the goals set out in this document.

Managing Water at Multiple Scales

Effective stormwater management requires addressing stormwater at the individual lot, community/neighborhood and regional scale.

Individual

Community

Regional

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Green Roofs

Consists of a permeable pavement (surface course) underlain by a uniformly-graded stone bed which provides temporary storage for stormwater runoff and promotes infiltration. The surface course may consist of porous asphalt, porous concrete or various porous structural pavers.

Implementing Green Roofs

A green roof can have up to twice the lifespan of a conventional roof, making the long-term cost of the two comparable. However, since the initial cost of a green roof is significant, a policy that focuses on alleviating construction cost burdens through subsidies will likely be most successful. Subsidies are usually provided per square foot of green roof area, up to an established maximum amount or percent of the total cost. The funding for subsidy programs may come from stormwater fees collected by the community to mitigate post-construction stormwater runoff. By investing in green roofs, a community can eliminate runoff before it enters the stormwater system. The use of public money on private land is validated through the reduction in gray infrastructure cost, size, and maintenance burden. Green roofs may also qualify as permitted obstructions to the maximum lot coverage regulations thus incentivizing their use.

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Rainwater Harvesting

Runoff capture and reuse encompasses a wide variety of water storage techniques designed to capture precipitation, hold it for a period of time, and reuse it. These storage techniques may include cisterns, underground tanks, above-ground tanks, rain barrels, planters or other systems.

Implementing Rainwater Harvesting

Implementing rainwater harvesting makes sense at the community level for several reasons. This technique can reduce stormwater collection overflows; reduce potable water demand when used for applications such as landscape irrigation; decrease the amount of energy required for treatment; and mitigate costs. Using a combination of incentives, compliance assistance and regulations can be very effective at obtaining a high rate of participation.

Incentives: Many cities, water districts, and conservation agencies offer free or discounted rain barrel to encourage residents to disconnect their downspouts and store rainwater on site. The use of subsidies and incentives can encourage the installation of rainwater harvesting, particularly among low income households. These programs can also be expanded to larger properties where storage and use of rain water can maintain commercial landscaping and on-site habitat, and have significant impacts on stormwater management capacity.

Compliance assistance: Providing brochures and self-help videos describing how to separate downspouts from the collection system, and offering free site assessments and technical assistance can be very helpful in achieving these goals. Cities such as New Orleans have partnered with local non-profit organizations to implement education and assistance programs encouraging rainwater harvesting.

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Trees

Trees are a vital part of our ecosystem. In addition to providing shade, which can reduce urban heat island issues, trees absorb and store water. Some species of trees, such as live oaks, are capable of absorbing 1000 gallons of water every day. That’s enough to fill 25 bathtubs. Trees also muffle street sounds, which increases the quiet, peaceful atmosphere that residents love about Baker.

Implementing Tree-Friendly Policy

From reducing stormwater runoff to improving the urban aesthetics and air quality, much is expected of a community’s trees. However, they are often given little thought as a risk reduction strategy and very little space to grow in inhospitable environments.

Tree planting/protection: Old growth tree protection regulations are a common strategy to maintain trees, such as live oaks, that provide the most benefit. Furthermore, tree canopy restoration can be accomplished by establishing tree planting requirements in commercial/mixed-use developments. Measuring success of these efforts is best accomplished through the establishment of citywide tree canopy goals (e.g. 50% tree canopy by 2030)

Planting standards: Through landscape ordinances, the requirement of adequate soil volume and quality soil can multiply the benefits of street trees. To obtain a healthy soil volume, trees should be provided large tree boxes, and adequate structural soils and root paths to allow growth of the root zone under sidewalks or other paved areas. These allow tree roots the space they need to grow to full size, increasing the health of the tree and providing benefits sooner than a tree with confined root space.

Stormwater absorption capabilities of common trees in southeast Louisiana

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Permeable Pavement

Consists of a permeable pavement (surface course) underlain by a uniformly-graded stone bed which provides temporary storage for stormwater runoff and promotes infiltration. The surface course may consist of porous asphalt, porous concrete or various porous structural pavers.

Implementing Permeable Pavement

With so many paved surfaces in the urban environment, there are numerous opportunities to increase permeability of sidewalks, driveways, parking lots, and roadways. Reducing runoff falls into two categories from a policy perspective: paved surfaces on private property and publicly owned paved surfaces.

Publicly-owned property: Unlike regulatory or incentive-based tools intended to influence private property owners, government agencies have much greater discretion to control what happens on public property. Green infrastructure can be incorporated into street design standards (e.g. reduced lane widths, permeable paving, street tree planting), bike and pedestrian investments ped lanes/sidewalks (e.g. permeable paving, street tree planting), tree lawns (e.g. stormwater bioswales), building sites (stormwater management strategies and pilot projects within publiclyowned sites such as schools and parks).

Private property:

Maximum lot coverage: A fundamental first step for reducing permeable surfaces is to identify maximum lot coverage standards in the zoning ordinance for all residential, commercial and industrial districts. Currently, maximum lot coverage is addressed in most residential districts, but only sporadically in non-residential districts despite the fact that these uses tend to have the most impermeable surfaces and thus produce the most runoff. These standards may be tailored to specific watershed units depending on localized flood risk.

Parking regulations: Sustainable parking management includes a variety of strategies that encourage more efficient use of existing parking lots and improved parking design. Current parking requirements are generally based on American Association of State Highway and Transportation Officials (AASHTO) or similar standards, but tend to be inflexible, overly generous with parking spaces, and don’t consider other benefits or drawbacks such as the amount of impervious surface or how paving may impact stormwater systems. The development of more accurate and flexible parking requirements means that parking standards will reflect parking demand, taking into account stormwater management factors. This may allow parking requirements to be reduced or square footage to be increased in exchange for implementation of strategies such as enhanced perimeter landscaping, shade trees, and permeable parking spaces and/or overflow parking areas to deal with occasional peaks.

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Rain Gardens

A vegetated shallow surface depression planted with specially selected native plants to treat and capture runoff. Rain gardens should be located in well-drained soils. They allow stormwater to be absorbed by plants and infiltrated into the groundwater.

Retention & Detention Basins

Two different kinds of ponds are often used for food control and stormwater runoff treatment: wet ponds and dry ponds. Both systems function to settle suspended sediments and other solids typically present in stormwater runoff. Wet ponds are called retention ponds and they have a permanent pool of water that fluctuates in response to precipitation and runoff. Dry ponds are designed to drain from a full condition within 36 to 48 hours to allow sediment particles and associated pollutants to settle and be removed.

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Bioswales

A broad, shallow channel densely planted with a variety of trees, shrubs, and/or grasses. Bioswales should be promoted in lieu of storm piping to convey stormwater naturally, promoting infiltration, reducing runoff volume, and filtering pollutants.

Bio Retention Implementation

Bioretention includes a range of strategies such as rain gardens, bioswales, and retention/detention ponds that can handle quantities of runoff from impermeable surfaces adjacent to where it is generated.

Compliance assistance: Providing how-to guides and connecting homeowners with those who can help with site assessments and technical assistance can be very helpful in achieving these goals. This may be another opportunity for partnerships with local non-profit organizations to implement education and assistance programs.

Regulations: Ambitious on-site retention standards in non-residential districts. Flexible landscape standards that encourage innovation and an appropriate mixture of plants and sub-surface structure to meet lot and adjacent stormwater conditions and needs.

Enhanced Stream Banks

A permanent area of trees and shrubs located adjacent to streams, lakes, ponds, and wetlands. Riparian forests are the most beneficial type of buffer for they provide ecological and water quality benefits.

Enhanced Stream Banks Implementation

Implementation: Riparian buffers are often established or restored through local development and zoning codes that identify critical floodways and riparian areas on a watershed scale. Wetlands, riparian areas, and floodplains prioritized for protection or restoration may be safeguarded through restrictions of potential development and the creation of conservation easements.

Incentives: For new projects, jurisdictions can offer double open space credit for the creation or enhancement of riparian buffers along protected waterways. They might also allow the transfer of development rights between a floodplain property and another located outside of the floodplain. This effectively stops any development on the property within the riparian buffer and, in turn, supplements the development potential of a property that has less adverse impact on the capacity of the watershed. Finally, jurisdictions might offer tax breaks or fee reductions for properties that enter into conservation easements that protect the riparian buffer.

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Floodplain & Wetlands Restoration

Floodplain and wetland restoration tries to mimic the interaction of groundwater, stream base flow, and vegetative root systems−key components of a stream corridor under pre-settlement (pre-1600s) conditions. The interaction among these elements provides multiple benefits, including the filtering of sediments and nutrients through retention of frequent high flows on the floodplain, removal of nitrates from groundwater, reduction of peak flow rates, groundwater recharge/ infiltration, reduced erosion, control non-native invasive species, and an increase of storage and reduction of food elevations during higher flows.