Ascension Parish, Louisiana and St. Tammany Parish, Louisiana: Conservation Planning and Zoning

Ascension and St. Tammany Parishes are two parishes or counties in Louisiana that are using planning and zoning to promote floodplain management and conserve green spaces. Each parish is contemplating how to preserve suburban and rural character through planning processes. In addition, each parish has crafted code language that allows it to conserve rural spaces by discouraging sprawl and floodplain development and by downzoning or decreasing developable density outside commercial centers. 


Ascension Parish 

Master Land Use Plan

In 2019, Ascension released an updated version of its Master Land Use Plan, which was approved by the parish’s Planning Commission.1 The plan includes eleven chapters charting a future vision for land use in the parish over the next 20 to 25 years including priorities for balancing population growth with drainage, floodplain management, and recreation and open space, among other considerations.2 In other words, the plan is “the parish’s blueprint for long-term development” but is not a regulatory document.3 

Over the past several decades, Ascension Parish has experienced rapid growth that has improved business prospects, job opportunities, and school rankings. Through the plan, Ascension Parish suggests the infrastructure requirements necessary to meet the demands of rapid growth. In particular, Ascension Parish aims to direct growth in a way that preserves and builds upon existing natural resources while also improving the overall quality of life in the parish. The plan contains recommendations on how parish leaders can transition Ascension from a once rural to a more suburban parish.4  

When creating the plan, Ascension Parish was guided by four principles: livable communities; transportation and infrastructure; recreation, open space, and natural environment; and economy and education.5 As a part of the livable communities principle, the parish will aim to preserve the parish’s rural character in areas where it still exists rather than in more suburban parts of the parish.6 The recreation principle emphasizes the importance of developing the parish in ways that protect natural resources and wetlands while also promoting and diversifying recreational opportunities.7 

Connected to those four principles, Ascension Parish also developed a Vision Map in the plan that identifies land-use strategies that will provide quality neighborhoods and housing options, attract young families, and retain older residents.8 In the Vision Map, the parish considers the impacts of different development types and patterns on infrastructure and highlights the effectiveness of Low Impact Development (LID).9 To manage growth, the parish will also aim to encourage new development on the West Bank, a neighborhood where growth has historically lagged behind the rest of the parish.10 

The parts that follow summarize some of the drainage, floodplain management, recreation and open space, and implementation provisions of the Master Land Use Plan relevant to growth and conservation in the parish.


Louisiana contains 40 percent of wetlands in the continental United States.11 In Ascension Parish alone, approximately 43 percent of the parish’s land — about 84,000 acres — consists of wetlands.12 However, both Louisiana and Ascension Parish are losing wetlands as a result of agricultural practices and forced drainage from developed areas.13 Rising sea levels, canal dredging, and channelization also contribute to wetland deterioration.14 Ascension’s topography is very flat, with only a 50-foot difference between the highest and lowest points in the parish.15 As a result, the water from heavy rains is slow to drain downstream and be pumped out.16 Ascension currently has two drainage districts — the East Ascension Consolidated Gravity Drainage District No. 1 and the West Ascension Consolidated Gravity Drainage District No. 1 —  responsible for establishing policies and operations and maintaining road ditches, off-road ditches, swales, major canals, and bayous.17 

As identified in the plan, Ascension intends on creating a master drainage plan for parish-wide drainage infrastructure. In the first stage of the plan, the parish created a Flood Management Implementation Plan, which evaluates policies, procedures, and enforcement practices. Ultimately, the assessment of current practices recommended that the parish clarify and update requirements and expand on the submittal requirements for development. In Ascension’s Master Land Use Plan, the parish builds upon these recommendations, suggesting that the Drainage Impact Study Policy be revised. The parish should update study requirements to ensure that detention methods are effective in 25 years.18 

In the plan, the parish recommends improving the existing drainage system. To do so, the parish would have to conduct a complete assessment of the drainage system and a review of major channels going to pumping to identify any problems.19 In the plan, the parish also discusses the potential effectiveness of establishing a drainage impact fee, a one-time fee paid only by new development to offset increases in impervious surface cover.20   

Floodplain Management 

Ascension has a history of flooding from the internal bayous and the Amite River, most often in February, April, August, and November. Since 1965, at least 12 major hurricanes and tropical storms have significantly damaged Ascension.21 About 56 percent of Ascension Parish is located within a designated Federal Emergency Management Agency (FEMA) floodplain. These designated areas, also called the Special Flood Hazard Area (SFHA), are at risk of experiencing a one-percent chance of a flood occurring each year.22 To protect properties in these areas, the parish currently requires that new buildings be elevated two-feet above the 100-year base flood level. 

The National Flood Insurance Program (NFIP) provides federally underwritten private flood insurance to homeowners. The Community Rating System (CRS) is a FEMA program designed to offset NFIP premiums and can lower property owners’ NFIP premiums by between five and 45 percent if local governments undertake a variety of actions. Ascension Parish participates in the CRS program and, as of May 2022, holds a Class 7 ranking, which reduces flood insurance premiums for parish residents by 10 percent for policyholders.23 In the plan, Ascension suggests it could review its existing floodplain development standards and update them as necessary to maximize future opportunities to get more CRS credits.24 In the plan, the parish also recommends the use of educational programs on maintaining ditches and conveyance channels to ensure that local stormwater is able to be captured. Educational programs can also provide details on ways to improve the parish’s CRS rating.25    

As the likelihood of severe flooding events increases over time, Ascension Parish could identify means to reduce potential impacts on floodplains. In Ascension, multiple structures experience repeated flooding. As of 2017, Ascension Parish had 261 repetitive loss and severe repetitive loss structures, 12 elevation projects, and nine acquisition projects.26 Using green infrastructure can benefit the parish’s flood management by absorbing rainwater, mitigating flooding, and reducing the impact of storms The parish can also lessen the risk of flooding by reducing development in floodplains and adopting higher floodplain management strategies.27

Ascension works to reduce flood risk by requiring the completion of Drainage Impact Studies before approving new development and building permit applications and limiting fill to 36 inches of the foundation on most lots.28 The plan highlights the potential to earn significant CRS credit by establishing ordinances with freeboard requirements and prohibiting the use of fill to meet height requirements to elevate structures.29 Fill increases runoff from properties. By reducing the amount of fill used to meet elevation requirements, development and subdivision ordinances can reduce localized flooding. In the plan, the parish suggests active and consistent enforcement of drainage regulations and fill restrictions across the parish.30 

In May 2018, Governor John Bel Edwards established the Louisiana Watershed Initiative, which aims to mitigate future flood risk with a focus on natural boundaries rather than jurisdictional boundaries. Since watersheds cross parish lines, the plan states that Ascension should continue to engage in the statewide initiative and collaborate with other local governments to manage watersheds.31 

Recreation and Open Space 

Throughout the community engagement process to inform the plan’s development, Ascension residents expressed a strong desire for access to recreational and open space opportunities. Centered around this community input, the plan aims to create a recreational and open space system that improves the quality of life in Ascension.32 The parish emphasizes the benefits of parks and open space in terms of their health, environmental, social, and economic values.33 One way the parish can protect and conserve open spaces is through floodplain management (see above), which can also serve as a tool to leverage co-benefits to both mitigate flood risk and improve water quality.34 In the plan, the parish also highlights how preserving and expanding recreational spaces in Ascension is an important sustainability and resiliency practice.35 Protecting natural resources is important to preserve scenic natural features and wildlife habitats for future generations. Also, recreational spaces, such as athletics fields, can be created as multifunctional spaces capable of retaining water during rain events.36 

To provide open space and access to nature, the parish plans to use green infrastructure, support the parish’s park and trail system, and pursue sensitive development of environmental areas.37 By lifting up its abundant natural resources, the parish can support the active lifestyle of its residents, contribute to their well-being, and make Ascension a more desirable place to live and work.38 In conjunction with its livable communities principle, the parish will also aim to preserve the parish’s rural character in areas where it still exists, a commitment Ascension residents support.39 The plan also identifies using universal design principles to increase accessibility to parks and recreational spaces. One principle includes building structures of adequate size and space to accommodate the use of all, regardless of a person’s body size, posture or mobility.40 

In the plan, Ascension recommends prioritizing improvements to the current park system before expansion projects.41 As such, Ascension can inventory existing parks and create a budget for adding multipurpose functions to existing parks. Expanding the functions of recreational parks will also diversify the stakeholders able to use the park amenities for different purposes.42 In these parks, the parish can also implement additional sustainability practices, such as resilient infrastructure and sustainable materials for parks and trails.43


The Master Plan also includes an implementation section that outlines priority projects and ways to measure progress with the plan’s objectives. Meant to be updated annually by the parish’s Planning Department, the implementation matrix tracks progress by detailing the timeframe, department, and status of each of the plan’s goals.44 The Priority Strategic Actions, described in the Vision, are the measures that should be undertaken first to fix pressing issues and demonstrate progress towards the parish’s vision for the future.45 

Through May 31, 2022, the parish was under a nine-month development moratorium for new subdivisions.46  During that process, the parish evaluated and approved updates to its Unified Land Development Code, which includes zoning regulations, to better balance population growth and increased flood risk.47  The final amendments to the Unified Land Development Code, which primarily focus on flooding and drainage, wetlands preservation, and traffic, were informed by the principles and recommendations in the Master Land Use Plan. 

St. Tammany Parish 

In 1999, St. Tammany released an updated version of its local comprehensive plan, New Directions 2025 (ND 2025). In developing the plan, residents cited a public desire to preserve low-density land use patterns, such as those that occur in the parish’s rural areas.48 These areas include agricultural and livestock operations, forests and timber, traditionally planned suburban districts, conservation districts, and other individual tracts of land.49 As provided in the plan, the parish is seeking to preserve that rural character by prioritizing land uses, such as reforestation, agricultural practices that protect water quality, and parks and preserves with protected natural features. Timber and livestock operations are also encouraged, along with best practices and regulations to protect water quality.50 

The parish’s comprehensive plan also identifies rural residential development as a high priority. The general support for this kind of development is derived from citizen feedback during the plan’s creation, and refers to a “very large lot or conservation subdivision.”51 Respondent feedback also revealed a strong desire to protect the parish’s green spaces and undeveloped areas. As stated in the plan, the parish’s land use regulations will need revisions and updates to adequately protect green spaces in accordance with these goals.52 The parish thus recommends actions that will call for new development to set aside portions of undeveloped green space that will be protected in perpetuity.53  

In ND 2025, the parish also recommends that the parish government expand and extend existing conservation areas and establish a network of contiguous open spaces, with the 100-year floodplain network serving as a starting point. Expected benefits of these actions include mitigating flood risk, providing community amenities, enhancing natural resources, and supporting recreational activities like hunting and fishing.

In addition to ND 2025, the parish’s local ordinances provide for different zoning provisions that can be used to enhance conservation. For example, the parish’s code recognizes several forms of suburban zoning districts, three of which promote single-family residential development in locations where the area’s character is protected by low-density development.54 The parish also has a Planned Unit Development District (PUD) and Rural (RO) overlays. The PUD overlay is used to allow development flexibility where, for example, existing regulations would not sufficiently protect environmentally sensitive features, or where increased regulatory flexibility would otherwise protect natural features or enhance the functionality and livability of the district. 

The RO is established to permit agricultural uses, to encourage the maintenance of the rural countryside, to preserve forests and other undeveloped lands away from areas of population growth, and to allow residents to retain their traditional ways of life.55 Only agricultural and residential uses are permitted in the RO, and no more than 25 percent of a lot can be covered by development.56  

Publication Date: May 20, 2022

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