Louisiana Watershed Initiative
View Resource at https://www.adaptationclearinghouse.org/resources/louisiana-watershed-initiative.html
Policymakers and planners should identify priority data needs to craft credible and useful solutions for flooding, drainage, and mitigation. Currently, more data are critical to inform legal, planning, policy, and project decisions at the regional, parish, and municipal levels. Some priority issues most relevant to the Regional Vision include the need for more: (1) forward-looking and comprehensive data; (2) inclusive data; (3) bridges and resources to translate and make data available for policymakers and the public to support resilience efforts.
Descriptions: Rain causing flooding in Hammond, Louisiana (left); Post-hurricane debris in Louisiana (right).
Credit: Rachelle Sanderson, Region Seven Watershed Coordinator, Capital Region Planning Commission.
Decisions around flooding, drainage, and mitigation must be data driven. There are publicly available data sources on food risk, but the data is often not presented in a forward-looking manner that analyzes and predicts future environmental and climate trends and impacts. For example, the Federal Emergency Management Agency (FEMA)’s National Risk Index (NRI) is an online mapping tool that can help communities across the United States understand their current relative risk and resilience related to natural hazards. The NRI identifies the relative vulnerability of all counties and U.S. Census tracts to 18 natural hazards including flooding. The relative vulnerability is based on detailed data and estimates of expected annual economic losses, social vulnerability, and community resilience. The NRI is intended to be used to aid local governments and communities in setting priority actions. Policymakers can use the NRI to identify where more refined risk assessments or improvements in building standards or codes may be needed. However, the NRI only uses historical data and does not incorporate climate projections, account for future hazard forecasts, or projected climate impacts.See footnote 1
Similarly, FEMA’s Flood Insurance Rate Maps (FIRMS) designate flood zones and capture risk at a moment in time for a series of storm events. These maps have legal relevance. At a high level, these maps are used to inform some federal flood insurance requirements under the National Flood Insurance Program. For example, if a resident lives in Flood Zone A and purchases a home with a federally backed mortgage, that resident must carry flood insurance. FIRMS also affect local land-use and zoning decisions and participation in the Community Rating System.
Despite the legal significance of FIRMS, they do not capture the future risk that communities may face as a result of sea-level rise, increased rainfall totals over shorter periods of time, and changing conditions as a result of development or the implementation of projects. This is critical in the context of the challenges facing Region Seven and others because these maps may become outdated with regard to environmental data.
Additionally, local jurisdictions can draw on tools like the National Oceanic and Atmospheric Administration’s (NOAA) Atlas 14 for precipitation frequency estimates (i.e., how much rain falls over how long and what event that correlates to). When local jurisdictions have ordinances that specify drainage standards, they can utilize this data. For example, for a ten-year, two-hour rain event based on NOAA Atlas 14, the City of Hammond, Louisiana can plan to build their drainage infrastructure to accommodate about four inches of rain. However, climate change is causing jurisdictions to accumulate more rain over less time.See footnote 2 Thus, in the future, a ten-year, two-hour rain event in that same location may result in about six inches of rain. Notably, after the most recent NOAA Atlas 14 update, several cities saw increased rainfall totals for a 100-year event.See footnote 3 According to NOAA, that update found “significantly higher rainfall frequency values in parts of Texas, redefining the amount of rainfall it takes to qualify as a 100-year or 1,000-year event.”See footnote 4 “In Austin, . . . the 100-year rainfall amounts for 24 hours increased as much as three inches up to 13 inches[, and] 100-year estimates around Houston increased from 13 inches to 18 inches and values previously classified as 100-year events are now much more frequent 25-year events.”See footnote 5
In addition to drainage infrastructure, Atlas 14 is used to “manage development in floodplains for FEMA’s National Flood Insurance Program.”See footnote 6 Here, incomplete or outdated data sets illustrate how one source of information can have cascading impacts affecting other agencies, levels of government, and communities.
From the federal to the state level in Louisiana, in June 2017, the Louisiana State Legislature unanimously approved the state’s 2017 Coastal Master Plan, which updates the state’s 2012 plan. Prepared by the Coastal Protection and Restoration Authority (CPRA), Louisiana’s Coastal Master Plans serve as a 50-year blueprint to guide hard structural (e.g., shoreline armoring, sediment diversion, and nature-based project investments to build a more sustainable coast.See footnote 7 The 2017 plan includes predictive models that analyze “future landscape and ecosystem conditions and the effects restoration and risk reduction projects have on those conditions.”See footnote 8 The predictive models “helped CPRA estimate the effects of projects on flood depths and direct economic damage” and “provide a holistic view of [Louisiana’s] coastal environment today and the changes [the state] can expect over the next 50 years.”See footnote 9As of summer 2021, CPRA is focusing on the 2023 Coastal Master Plan Update. This plan is one example of data presented in a forward-looking manner. However, the plan only looks at flooding on the coast. The “Great Floods of 2016” (see Introduction) highlighted a need to look at flooding more comprehensively across watersheds from the inland to coastal spectrum.
In response to the need for more comprehensive flooding data and the 2016 catalyst, in 2018, Governor John Bel Edwards launched the Louisiana Watershed Initiative (LWI). In 2019, the state recognized that one of the challenges associated with achieving statewide flood-risk reduction was a lack of current, reliable data to help determine future flood risks. Louisiana also identified flooding as a cross-jurisdictional issue necessitating more collaborative investments in data collection and modeling.See footnote 10
The state is working to address some of these data deficiencies through the modeling and data and rain and river gauge network programs.See footnote 11 Through the modeling and data program, the state is partnering with consultants to develop statewide hydrologic and hydraulic models.See footnote 12 Through the rain and river gauge network program, the state is installing additional rainfall and streamflow gauges through a gauge network that will contribute to the overall understanding of flood risk as it relates to rainfall and stream flows and heights. However, as of summer 2022, these data are not available yet. Further, parishes and municipalities may need different types and levels of data to inform locally relevant and specific decisionmaking efforts.
Data sets that include analysis and predictions about future trends and impacts will allow decisionmakers to create laws, plans, and policies that more comprehensively take into account the impacts facing communities and better prepare them to adapt to changing conditions.
Beyond a lack of sufficient forward-looking data, there are a few other priority trends that are worth noting. First, the data presented in tools and reports is more often quantitative rather than qualitative. Quantitative data is quantifiable, numerical data. Conversely, qualitative data is data that can be observed (e.g., through interviews) but necessarily cannot be measured on a numeric scale.See footnote 13 A lack of collecting and analyzing quantitative and qualitative data together leads to an absence of informed and holistic decisions around flood resilience. Second, data disproportionately leaves out Black, Indigenous, and People of Color (BIPOC), and low-income communities.See footnote 14 These deficiencies fail to paint a full picture of the actual flood risk facing a community and concurrently lead to incomplete decisions.
In addition to challenges with risk assessment data, currently, there are not enough tools or examples available for policymakers to translate this data into decisionmaking. Specifically, policymakers and communities require accessible and user-friendly tools, resources, and technical assistance to identify and assess the benefits and tradeoffs associated with different flood mitigation options and adaptation tools and strategies to build resilience. There are some legal and policy toolkits and databases that present a suite of potential flood mitigation options — from structural elevations to buyouts to drainage basins and retention ponds — local governments and communities may consider to adapt to flooding. However, there are few mediums that link actual flood risk data for a given locality together with potential adaptation options to support legal, planning, policy, and project efforts. More data is needed to communicate with policymakers the anticipated or actual benefits from investing in flood data and mitigation to justify past and support continued investment in these efforts.
Beyond parish and municipal governments, public access to data about flood and housing risk is also limited. At present, not enough data is accessible. Creating data tools can also be useful for accountability and transparency purposes as well as monitoring the implementation of plans, laws, policies, or projects.
Given the foregoing, policymakers in Region Seven and beyond should consider how to better identify priority data needs around flooding, drainage, and mitigation options to inform legal, planning, and policy decisions at the regional, parish, and municipal levels, especially in BIPOC and low-income communities.
This part presents four separate, but related elements that regional and local governments can consider to make progress on this objective:
These elements can be explored separately or together. However, they are all well connected and can build on one another to ideally support more complete and comprehensive decisionmaking efforts. Regardless, at the start of every process, parish and municipal governments should first identify their priority data needs. These priority needs should be guided by the goals and parameters of the relevant decisionmaking effort and informed by community input. This initial step can more effectively shape a landscape assessment of what types and sources of data already exist and where new data is required. When looking at this objective, decisionmakers should also look to Objective 5.3, which expands considerations in this part to evaluating flood mitigation decisions in the context of affordable housing, infrastructure, and green spaces.
Data-driven decisions around flooding, drainage, and mitigation should ideally use a mix of quantitative and qualitative data sets. When identifying priority data needs and utilizing data to inform legal, planning, policy, and project decisions at the regional, parish, and municipal levels, quantitative data should be integrated and aligned with qualitative data to enable more comprehensive approaches to “greaxing” or growing resilience.
In regards to flooding, quantitative data may include data about land use, future precipitation patterns, and demographics over different geographic and temporal scales. Quantitative data sets can be produced by governmental entities (e.g., United States Census Bureau) or nongovernmental entities (e.g., Headwaters Economics). In pursuit of this objective specifically, regional and local governments will have to find ways to access, maintain, and update these types of data, in addition to combining them into one or a few usable platforms. Integrated or coordinated data mechanisms can draw more attention to the relationship between these sectors to better support holistic decisionmaking efforts.
Moreover, qualitative data may include information about people’s cultural and emotional ties to land, community perspectives about climate issues, and stories about the personal impacts of flooding. To gather qualitative data, residents can provide important data points based on their local knowledge and lived experiences to inform vulnerability assessments and identify priority resilience goals and needs. Parish and municipal governments should evaluate strategies and partnerships to work directly with residents and community-based organizations to learn from them in ways that honor and respect their histories and insights (for recommendations and best practices for community engagement generally, see Objective 5.1).
In pursuing quantitative and qualitative data jointly, policymakers will have to evaluate how to bring both sets and types of information together in ways that accurately and meaningfully illustrate the bigger picture of flooding in communities changing over time and simultaneously support legal, planning, policy, and project decisions.
Existing Sources of Data
There are currently various publicly available sources of flooding data produced by public or private entities that could be relevant for parishes and municipalities in Region Seven. These sources of data may include tools that analyze just flood risk or social vulnerability, or sources that integrate both. This part of the objective lays out a few examples of each type of tool that may be of interest to parish and municipal policymakers in Region Seven. However, this objective is not intended to present an exhaustive list of all of the potential tools and resources, let alone those that are specific to or have been developed by individual jurisdictions.
In Louisiana, decisionmakers can use the Louisiana FloodMaps Portal from Louisiana State University’s College of Agriculture to determine information like flood risk over different geographic and temporal scales. The portal includes FEMA FIRMS and a scenarios guide and tool to evaluate different designs and elevations for homes and other structures relative to base flood levels.
Another example is First Street Foundation’s Flood Factor, a free online tool Americans can use to determine their property’s flood risk and understand the ways that flooding is changing due to climate change. Flood Factor is the first publicly available, peer-reviewed tool to consider changes in the environment due to climate change and as a result, illustrate how property-related flood risks change over time. Flood Factor determines any location’s probability of flooding from four major sources and how they are influenced by future conditions like sea-level rise: rain, riverine, tidal events, and storm surge. People can use the tool to evaluate flood risk on two different scales for individual properties and across larger areas like parishes or counties. Flood Factor can serve as a crucial source of information for property owners, in addition to regional and local policymakers and infrastructure agencies, among other decisionmakers and stakeholders. As such, Flood Factor can help inform decisions like where people might choose to live and support future development and adaptation decisions.
The Center for Disease Control’s Social Vulnerability Index (SoVI) is one example of a publicly available tool for assessing social vulnerability. County-level socioeconomic and demographic data collected from 2006 to 2010 were used to construct the index of social vulnerability to environmental hazards for the United States. SoVI graphically illustrates the geographic variation in social vulnerability at a county level. It shows where there is an uneven capacity for preparedness and response, and where resources might be used most effectively to reduce the vulnerability. SoVI also is useful as an indicator in determining the differential recovery potential from disaster events.
The previous examples are of data sources that analyze flood risk and social vulnerability separately. Neighborhoods at Risk is a free, online data tool from Headwaters Economics that provides information about how communities across the United States are being impacted by climate change and integrates data about both flood risk and social vulnerability. In particular, the tool displays which communities “may experience unequal impacts from hurricanes, flooding, and extreme heat.”See footnote 15 Neighborhoods at Risk’s data is regularly updated and is an easy way to see what the top vulnerabilities are for any community with data about people and climate exposure. The tool and the integration of both flood risk and social vulnerability data together can enable policymakers, community leaders, and others to make more comprehensive and well-rounded decisions with equity, local context, and people in mind.
Credit: Neighborhoods at Risk, Headwaters Economics, https://headwaterseconomics.org/apps/neighborhoods-at-risk/ (last visited June 14, 2022).
Publicly available sources of data like the above examples can be a great aid to policymakers engaging in resilience legal, planning, and policy conversations. This tool can help a community gain a better understanding of what climate and social vulnerabilities exist and should be managed. Based on these vulnerabilities, governments and other decisionmakers can make better investments for future development.
In addition to federal and state resources, policymakers can also keep an eye out for private ones. However, across the board, parishes and municipalities should first learn about the different types of data included in each tool and any potential shortcomings to be able to weave them together in one picture to support comprehensive decisionmaking efforts (e.g., is social equity data available, what types of flooding are included, are residential land use and road network overlays available?). At the start of decisionmaking processes, policymakers should spend time assessing what sources of data exist that align with their priority data needs and can inform legal, planning, and policy decisions. Understanding what kind of data already exists can potentially save time and resources since certain analyses may have already been conducted. When gathering this type of data intel and background, jurisdictions should make sure they can verify the authenticity, quality, and accuracy of the data, which can include using reliable sources and checking the methodology of data collection.
Where publicly available or existing information does not fit the bill, policymakers may then have to consider investing in new sources.
For identified priority data needs, decisionmakers may require data that does not already exist or is for some other reason unavailable to them. For example, decisionmakers may assess that they require more holistic data analyses that take both quantitative and qualitative data into account, or current data is not at the scale that is appropriate to support the necessary level of decisionmaking. Regions, parishes, and municipalities can consider collecting their own data to support priority data needs and decisionmaking processes around flooding, drainage, and mitigation. This process will likely include collaborating with other expert entities like universities, consultants, and community-based organizations. Other considerations for assessing future data needs may include determining how data will be collected, analyzed, managed, and updated; where the data will be housed; if the data will be publicly available and if so, how it will be presented to the public.
From the outset, decisionmakers should clearly determine how they will use the data in the context of building resilience. To avoid wasting limited time and resources and maximize resilience efforts, parish and municipal governments must be sure that the data collected directly supports their legal and policy decisions around flooding, drainage, and mitigation. For example, Charlotte-Mecklenburg Storm Water Services (CMSWS) is a joint municipal–county stormwater utility that manages and maintains the regulated floodplains within Mecklenburg County, North Carolina, including the City of Charlotte. CMSWS has developed a system for assessing community flood risk through the Mecklenburg County Risk Assessment/Risk Reduction (RARR) Tool for comprehensive mapping, impact analysis, and county-wide floodplain management. This map-based application allows the agency to collect and analyze flood risk data to help identify and reduce flood risk at the parcel level and regionally. RARR is a data-driven framework and set of tools that dynamically assess, evaluate, and ultimately prioritize flood mitigation strategies.
To help identify the economic value of structures that have been saved from flooding by implementing mitigation strategies, CMSWS also created the Loss Avoided Tool — deemed a “sister tool” of the RARR Tool that runs on the same online platform. CMSWS runs the Loss Avoided Tool after every flood in Mecklenburg County to calculate losses avoided due to mitigation investments that have already been implemented. This tool helps CMSWS predict losses avoided by calculating flooding depth in inches and feet — in terms of what structures would have flooded and what the associated monetary cost would have been before the mitigation actions were deployed.
These results work to bridge the gap between access to the technical data and communicate the successes of the RARR program with policymakers and the local community. Over the last twenty years, CMSWS has invested about $65 million in state, federal, and local funds, and saved about $30 million through avoided losses. This combination of a real-time flood monitoring and risk mitigation tool with a loss avoided component can be replicated by other stormwater or drainage authorities or regional and local governments to demonstrate the fiscal, social, and environmental benefits, among others, of investing public dollars into resilience strategies and data-driven decision-support tools.
In addition to direct legal and policy support, governments should aim to provide the public with data in ways that are accessible and can allow both policymakers and communities to track and adaptively manage implementation progress, as necessary, For example, the New York City Rezoning Commitments Tracker (Tracker) is an online tool developed by the city that enables local residents to monitor the Big Apple’s steps to implement several neighborhood-level comprehensive plans. The neighborhood plans, referred to generally as “rezonings,” include zoning code changes as well as city commitments to specific capital and programmatic investments. The tool can be used to both inform the city’s internal coordination and project management as well as provide external transparency for community members. The Tracker also helps users understand how zoning changes will manifest in tangible projects, translating the technical information from neighborhood rezoning plans into specific initiatives. In addition, in its 2017 Coastal Master Plan, Louisiana created the Master Plan Data Viewer, which is an interactive tool that allows “residents to view potential flood risk to their community or property over time as well as land loss projections and various socio-economic factors across the coast” and “provides updated information on the implementation of projects.”See footnote 16 Using and maintaining data in this manner is another way to support and implement community-led decisionmaking processes that can in turn increase community capacity and capability to greaux regional and local resilience.
When identifying priority data needs around flooding, drainage, and mitigation options to inform legal, planning, and policy decisions at the regional, parish, and municipal levels, decisionmakers may consider the following practice tips:
These tips are based on priority implementation best practices and considerations most relevant to this specific objective and do not present an exhaustive list for regional and local planners and policymakers.
It is important to acknowledge that every jurisdiction will be starting from a different place and have a unique local context and needs, among other factors. Therefore, these practice tips could be adopted individually, collectively, or not at all. It will be up to policymakers to work directly with their communities and other key stakeholders and partners to assess and determine potential tools and approaches to implement this goal and objective.
The summaries below highlight resources and case studies available in Georgetown Climate Center’s Adaptation Clearinghouse that are relevant to this objective. They illustrate how many of the above benefits, practice tips, and planning, legal, and policy tools were or are being evaluated and used in practice in different jurisdictions. To learn more and navigate to the Adaptation Clearinghouse, click on the “View Resource” buttons.
1. Frequently Asked Questions, Nat’l Risk Index, View Source (last visited Apr. 19, 2022). | Back to contentBack to content
2. Vincent M. Brown et al., Trend Analysis of Multiple Extreme Hourly Precipitation Time Series in the Southeastern United States, 59 J. Applied Meteorology & Climatology, 427–42 (2020); David J. Mitchell, Does it seem like it's raining harder? Here's what these LSU researchers found., The Advocate (Aug. 2, 2021, 4:00 A.M.), View Source. | Back to contentBack to content
3. NOAA Updates Texas Rainfall Frequency Values, Nat’l Oceanic & Atmospheric Admin. (Sept. 27, 2018), View Source. | Back to contentBack to content
7. Coastal Prot. & Restoration Auth., Louisiana’s Comprehensive Master Plan for a Sustainable Coast 30 (June 2017), available at View Source (“In 2005, following Hurricanes Katrina and Rita, the Louisiana Legislature established CPRA and set in motion the creation of a comprehensive master plan for our coast that would be updated every five years with the best available information, and a fiscal annual plan that details the funding and implementation schedules for projects.”). | Back to contentBack to content
8. Id. at 70. Back to contentBack to content
10. La. Office of Cmty. Dev., Master Action Plan for the Utilization of Community Development Block Grant Mitigation Funds (CDBG-MIT) 43 (2019), available at View Source. | Back to contentBack to content
11. Statewide Data and Modeling Program, La. Watershed Initiative, View Source (last visited Apr. 19, 2022). | Back to contentBack to content
12. What’s the Difference Between Hydrology and Hydraulics?, Foresite Grp., View Source (last visited Apr. 27, 2022) (“Hydrology is the study of rainfall and water, especially its movement, in relation to land. . . Hydraulics is concerned with the conveyance of water through pipes and channels.”). | Back to contentBack to content
13. Dr. Saul McLeod, What’s the difference between qualitative and quantitative research?, Simply Psychology (2019), View Source; Quantitative vs. Qualitative Data, Mac Dewitt Wallace Library (Mar. 9, 2021), View Source. | Back to contentBack to content
14. See, e.g., Amy Hawn Nelson et al., Actionable Intelligence for Social Policy, Univ. of Pa., A Toolkit for Centering Racial Equity Throughout Data Integration 2–3 (2020), available at View Source (“Black, Indigenous, and people of color (BIPoC) and/or people living in poverty are often overrepresented within government agency data systems, and disparate representation in data can cause disparate impact. . . . [W]e must embed questions of racial equity throughout the data life cycle: [(1) in planning; (2) in data collection; (3) in data access; (4) in algorithms/use of statistical tools; (5) in data analysis; and (6) in reporting and dissemination] . . . Acknowledging history, harm, and the potentially negative implications of data integration for groups marginalized by inequitable systems is a key first step, but it is only a first step. To go beyond this, we must center the voices, stories, expertise, and knowledge of these communities in decision making, and take collective action with shared power to improve outcomes and harness data for social good.”). | Back to contentBack to content
15. About Us, Headwaters Economics, View Source (last visited Mar. 21, 2022). | Back to contentBack to content
16. Coastal Prot. & Restoration Auth., Louisiana’s Comprehensive Master Plan for a Sustainable Coast 20 (June 2017), available at View Source. | Back to contentBack to content
17. See, e.g., Amy Hawn Nelson et al., Actionable Intelligence for Social Policy, Univ. of Pa., A Toolkit for Centering Racial Equity Throughout Data Integration 2–3 (2020), available at View Source (“Black, Indigenous, and people of color (BIPoC) and/or people living in poverty are often overrepresented within government agency data systems, and disparate representation in data can cause disparate impact. . . . Acknowledging history, harm, and the potentially negative implications of data integration for groups marginalized by inequitable systems is a key first step, but it is only a first step. To go beyond this, we must center the voices, stories, expertise, and knowledge of these communities in decision making, and take collective action with shared power to improve outcomes and harness data for social good.”). | Back to contentBack to content
18. Id. at 3 (“[W]e must embed questions of racial equity throughout the data life cycle: [(1) in planning; (2) in data collection; (3) in data access; (4) in algorithms/use of statistical tools; (5) in data analysis; and (6) in reporting and dissemination].”). Back to contentBack to content
19. Na’Tisha Natt, Louisiana Housing Corporation Launches New Interactive Data Map To Support Affordable Housing Policies, La. Hous. Corp. (July 22, 2019), View Source; PolicyMap, La. Hous. Corp., View Source (last visited Mar. 22, 2022). | Back to contentBack to content
20. La. Hous. Corp., Louisiana Housing Corporation – PolicyMap Mapping Tool Data Directory (2019), available at View Source; Na’Tisha Natt, Louisiana Housing Corporation Launches New Interactive Data Map To Support Affordable Housing Policies, La. Housing Corp. (July 22, 2019), View Source. | Back to contentBack to content
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