Spring Up! Denham Springs Masterplan

SPRING UP!

Denham Springs Masterplan

SPRING UP!

Denham Springs Masterplan

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CREDITS

This publication and the semester-long design studio it represents were made possible through grant support from the Gulf Research Program of the National Academies of Sciences, Engineering, and Medicine and the Robert Wood Johnson Foundation, as well as a generous gift from the Chevron Gulf of Mexico Business Unit. The LSU Coastal Sustainability Studio brings together disciplines that frequently conduct research independently —such as design, science, engineering, and planning— to intensively study and build integrated design applications that respond to critical issues of coastal settlement, restoration, flood protection, and economic development. The CSS builds university capacity and transdisciplinary teams that work to solve coastal and deltaic problems through an integrated design and systems thinking approach.

Research helps inform decision-makers, public policy, and efforts to plan for the future, such as the State of Louisiana’s Coastal Master Plan.

CSS LEADERSHIP Interim Managing Director Traci Birch, PhD, AICP Assistant Director Mary Bergeron Executive Committee Chairman and Interim Executive Director Robert Twilley, PhD Executive Committee Members: Sam Bentley, PhD Mark Boyer Craig Colten, PhD Marwan Ghandour Margaret Reams, PhD Clint Willson, PhD and PE

TEAM The design team led by Assistant Professor Brendan Harmon included the following students: Josh Black Peihong Han Chadd Hippensteel Xiaoman Ji Sophie Lott Murong Xu Yue Zhang IN COLLABORATION WITH Prof. Clint Willson, LSU College of Engineering LSU Civil Engineering students in CE 4260 Hydrologic Design ACKNOWLEDGMENTS Mayor Gerard Landry, City of Denham Springs Jeanette Clark, City of Denham Springs Assistant Professor Douglas Carlson, LSU Louisiana Geological Survey SUPPORT LSU Coastal Sustainability Studio National Academy of Sciences Robert Wood Johnson Foundation Chevron Corporation, Gulf of Mexico Business Unit

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00 CONTENTS

01 INTRO 02 ANALYSIS 03 GREEN INFRASTRUCTURE 04 PARTICIPATORY DESIGN 05 MASTERPLAN 06 SITE DESIGN * ARRANGED BY SECTIONS

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01 INTRO

The aim of this project was to help the city of Denham Springs envision a more resilient future by identifying and illustrating potential interventions for building resilience. Our design work was part of a greater initiative by the LSU Coastal Sustainability Studio – the project Inland from the Coast: A multi-scalar approach to regional climate change responses – that seeks to build resilience to inland flooding and climate change in Louisiana. The designs were meant to help communities at risk of flooding develop policies and build their capacity to win funding and grants for implementation. Through a participatory design process we identified strategic opportunities for green infrastructure that could reduce flooding and help the community develop a healthier relationship with water. Graduate landscape architecture students in their final studio course worked on this project – creating maps, running a participatory design workshop, developing a masterplan based on community input, and designing site scale interventions. They collaborated with civil engineering students to investigate green infrastructure interventions for reducing flooding in the community. They engaged the community with a participatory design workshop that included community mapping, a streestcape model for interactively designing complete streets, and informational boards on green infrastructure, complete streets, and flood resilience. Building on community input from the workshop, the proposed design interventions included a complete street with green infrastructure, city parks with flood storage, and a riparian park and greenway. The masterplan and design interventions were presented to the city government and displayed publicly at the community’s annual Spring Festival. I would like to thank the LSU Coastal Sustainability Studio, the National Academy of Sciences, and the Robert Wood Johnson Foundation for making this possible.

Brendan Harmon Assistant Professor Robert Reich School of Landscape Architecture Louisiana State University

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02 ANALYSIS

The graduate studio visited Denham Springs and the surrounding area throughout the Spring 2019 semester. The area that the studio focused on spanned from North College Street in the north, Railroad Avenue in the south, the Amite River in the west, and Pete’s Highway in the east. Some of our key findings were the high percentage of impervious surfaces in some of the highest points of the city, traffic congestion along North Range Street, a lack of pedestrian crossings and sidewalks, degradation and lack of accessibility along Long Slash Branch, and the potential for green space and rainwater capture in underutilized or abandoned lots such as the abandoned concrete factory. Additionally, the team used GIS mapping to better understand flood and run-off related issues.

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Context

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ANALYSIS

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Hydrology

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ANALYSIS

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This map shows a Digital Elevation Model (DEM) of the Long Slash Branch Watershed with 1ft contours located in Denham Springs. It is interesting to see the relatively high elevation of the Antiques District along North Range Street and the low elevations that persist through the entirety of Long Slash Branch and in the eastern portion of the watershed.

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ANALYSIS

Vegetated Creek Concrete Canal Rainfall Flow Direction Stream Flow Direction

This hydrological map shows the direction of runoff and stream flow towards and along Long Slash Branch.

The eastern portion of the watershed is of interest since water flows to the east during low flow levels and likely flows west towards the Amite River during high flow times. This is an interesting feature of some South Louisiana bayous.

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Type

% of Watershed

Low Story Vegetation

25%

High Story Vegetation

30%

Impervious Surfaces

22%

Grass

23%

This is a land cover map showing the different types of surfaces found in the watershed. Although impervious surfaces do not account for the majority of the watershed, they are concentrated in certain areas and can be a source of rapid water flow towards Long Slash Branch. Increasing the vegetation density in these impervious areas, especially along North Range Street could help to reduce flooding. We derived a Manning’s roughness map from this land cover.

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ANALYSIS

Flood Scenario

Amite River Gauge Level 13m + 2in of rain/hr for 3.5hr

This map represents the flood scenario detailed above. One can see the effect of high water levels in the Amite River and how close it backs up towards Denham Springs. River levels at this height slow water discharge exiting Long Slash Branch which then backs up the branch and likely spills its banks. It is also interesting to see where water concentrates along Long Slash Branch. Capturing water upstream and reducing or slowing rainfall flow towards the branch is one way to help reduce flooding downstream.

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03 GREEN INFRASTRUCTURE

The studio researched various green infrastructure practices to incorporate into the masterplan for Denham Springs. Each student researched a specific intervention appropriate for the site and developed an informational board to display at a community participatory design meeting. Each board included information about the green infrastructure practice, a rendering of the intervention, and precedent imagery.

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Bioswales

Pervious surface to improve the infiltration process

Plants to slow down surface water

Pedestrian Path

Bioswales are shallow, vegetated drainage channels with gently sloping banks for managing stormwater.

Bioswales are used to slow and filter stormwater, collect sediment, and recharge groundwater.

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GREEN INFRASTRUCTURE

Retention Ponds

Water Inflow

Retention ponds collect and store stormwater, reducing peak flows and surface runoff during storm events and allowing sediment and pollutants to settle.

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Floodable Parks

Clean pollutants from water before it re-enters waterways.

Temporarily holds stormwater runoff Street runoff flows into site

Floodable parks function as retention basins during storm events, while providing recreational, aesthetic, and ecological services during regular conditions.

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GREEN INFRASTRUCTURE

Green Roofs

Vegetation Growth Substrate Filter Fabric Drainage Element Protection Layer Root Barrier Insulation Layer Water Proofing Membrane Roof Deck

Green roofs are vegetated roofs that can reduce stormwater runoff, regulate building temperatures, reduce urban heat island effects, and serve as habitat for birds and insects.

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Rain Gardens

Rain gardens are shallow, vegetated depressions for capturing and storing stormwater. Rain gardens slow and filter stormwater, recharge groundwater, and can serve as habitat for wildlife.

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GREEN INFRASTRUCTURE

Naturalized Creeks

Naturalized creeks are restored waterways that had previously been channelized. Naturalized creeks slow stormwater, recharge groundwater, create opportunities for recreation, and can serve as habitat for wildlife.

Their banks can be armored with stone, gabions, woody vegetation and debris, or fascines.

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Complete Streets

Complete Streets are streetscapes that offer multimodal transit including vehicular, pedestrian, and bicycle traffic, while prioritizing safety and accessibility, managing stormwater, and enhancing aesthetics.

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GREEN INFRASTRUCTURE

Complete Streets

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04 PARTICIPATORY DESIGN

After the initial individual design development phase, the studio broke up into two groups to develop two potential masterplans to share with the community. The overall layout of potential areas for water management or green infrastructure interventions ended up similar; however, each group included unique interventions. Masterplan A focused on reshaping the Long Slash Branch Creek and developed a green loop that would improve pedestrian circulation for the nearby schools, antique district, and access to the creek. Masterplan B focused on a trail connection to the Amite River and proposed a bike connection between Denham Springs and Baton Rouge that follows the existing train tracks.

An important part of the studio was getting community feedback through a meeting with the community. The studio came up with five interactive methods of participatory design engagement, including: the two masterplans, green infrastructure informational boards, a flood map to capture individual experiences of flooding, a “wants” model to capture what programming the community wants to see and where, and a complete street model to show different opportunities for improving the North Range streetscape.

The participatory design meeting happened in conjunction with a Bike Pedestrian workshop on Tuesday, March 19, 2019, from 5:00 pm – 7:00 pm at the Healing Place Church in Denham Springs. The range in visitor occupations included non-profit employees, a hairdresser, an architect, council members, arts council members, and a doctor’s office assistant. The studio received feedback from the community that highlighted the following concerns: pedestrian and bike access, lack of programming for children, antique district streetscape, and access to the river. This feedback helped determine the final selection of sites for further design development.

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Masterplan A

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PARTICIPATORY DESIGN

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Masterplan A

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PARTICIPATORY DESIGN

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Masterplan B

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PARTICIPATORY DESIGN

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PARTICIPATORY DESIGN

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05 MASTERPLAN

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06 SITE DESIGN

Following the participatory design process, each student selected an area of the masterplan to develop further. The following pages will include a sampling of each site’s design.

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Sophie Lott

The goal for the Range St. area of the Masterplan is to utilize green infrastructure to filter and mitigate stormwater runoff, to improve pedestrian access to the antique district, and to slow down traffic. This implementation will help the antique district become a destination and boost business. The strategy is to take the Centerville St. intersection and turn it into an accessible roundabout which also cleans and transfers water to Long Slash Branch Creek. North Range’s streetscape would include raised pedestrian paths, filtration planters, street trees, and details that are inspired by the circular shape of a spring.

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SITE DESIGN

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SITE DESIGN

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SITE DESIGN

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SITE DESIGN

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SITE DESIGN

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Josh Black

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SITE DESIGN

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Peihong Han

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SITE DESIGN

Arts Council Livingston Parish Denham Spring City Hall

Green Slope Plaza Outdoor Cafe

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Chadd Hippensteel

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SITE DESIGN

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Xiaoman Ji

RIPPLE LAND __ OVERFLOW POND SECTIONS

MASTER PLAN

SECTIONS

B’

OVERFLO

C’

SECTION A-A’

A-A’ A’

B

A-A’

C A

A’

B-B’ 0 10

50

100

B-B’ B

200ft

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0 10

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50

100

200ft B-B’

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50

100

200ft

Canal N C-C’

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STRATEGY

Tear down the abandoned church

Tear down the abandoned Change the impervious surfaces church PERSPECTIVE 64

SITE DESIGN

Change the impervious surfaces

Change the impervious surfaces

Reuse d BIRDthe EYE

SECTIONS

MLA A-A’OVERFLOW

XIAOMAN JI

POND

B-B’

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100

SECTIONS

200ft

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Reuse the dig out soil Canal

BIRD EYE VIEW C-C’

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Reuse the dig out soil

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Murong Xu

Located in the center of Denham Spring downtown, the creek park is faced with highly complex traffic issues and plays a vital role in connecting separate surroundings. The proposed new plan for this park is aimed to provide the public with more accessible and safe approaches to walk across roads or walking along the creek, creating a walking-friendly district.

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SITE DESIGN

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Yue Zhang

The site is located at the end of Long Slash Branch. It could be considered as the destination where the water flows into for this area. Therefore, a retention pond is created for absorbing the stormwater and hold the water permanently. Around the retention pond, there are many facilities and programs are installed like amphitheater, water splash pad, playground, sport courts, skateboard park, pavilions. Also, there are many events are introduced such as Art Market, Food Court, Band Performance, Spring Fest etc.

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SITE DESIGN

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