Urban Watershed Framework Plan: A Reconciliation Plan For Conway

Project Description
The Framework Plan shows that repair of degraded urban watersheds can be a powerful agent for reinventing the physical environments of post-industrial cities. More than half of America’s waterbodies are unsafe for swimming, fishing, and as sources of drinking water due to anthropogenic activity. Considering that city and watershed generate conflicting shape and structure across the landscape, how can city form fix the watershed to deliver ecosystem services? The Plan pioneers an innovative developmental vocabulary for universal application in “wet” cities, showing what a comprehensive design-based urban watershed plan looks like. The Plan introduces watershed management principles into urban design for a fast-growing city with severe water management problems. The project invents a transferable planning vocabulary aligning the city’s metabolism with that of the watershed. A portfolio of modulated green infrastructural retrofits provides value-added work to conventional urban infrastructure investments. Green infrastructure, incorporating urban rain terrains (holding water) and riparian corridors, delivers ecosystem services benchmarked to the Ecosystem Services Concept, a matrix of 17 ecological services delivered through higher-order transformations of degraded ecosystems.

Aligning Urban and Ecological Metabolism
The Framework Plan is one part in a multi-pronged initiative by the EPA and the Arkansas Natural Resources Commission to mitigate severe urban water management problems in the Little Creek-Palarm Creek sub-watershed incorporating the City of Conway, Arkansas (pop. 62,500). Conway, the state’s second fastest growing city in the nation’s 75th fastest growing county, resides within a designated Priority Watershed. The sub-watershed drains approximately 42 square miles and contains five polluted urban headwater streams exhibiting advanced urban stream syndrome. The immediate goal is the removal of these streams from the Arkansas Department of Environmental Quality 303(d) list of impaired water bodies. Urban sedimentation and stormwater runoff are contributing to the continued decline of Lake Conway downstream. A major natural and economic asset to the area, Lake Conway at 6,700 acres is the largest reservoir in the U.S. built by a game and fish commission. Since Conway averages 51” of rainfall annually—30% more than the national average—the Framework Plan reconciles urban growth with a green infrastructure incorporating urban rain terrains (based on holding water) and riparian corridors (based on drainage). Rather than limit downtown Conway’s current growth and push growth further out, the goal of the Framework Plan is to equip urban infrastructure and land uses to deliver the 17 ecosystem services found in all healthy ecosystems, including regulation of flooding and water pollution. Collateral benefits of reconciliation between city and watershed include greater livability, sustained economic development, improved community resilience to disruption and shocks, and a civic landscape that expresses enduring environmental value. Project sponsors wanted a transferable and scaled planning vocabulary for application in city-watershed interface planning elsewhere.

A Transferable Urban Design Vocabulary for Resilience
The Framework Plan’s design tools and planning vocabulary provide communities with a transferable resilience framework to restore urban watersheds though urban design. The challenges in implementing resilience or risk-based decision-making in urban systems include the lack of a common language of assessment and management for the characteristics that makes those systems resilient. We need a language of resilience design and management that aligns with the language of city ordinances and policies. The Plan employs the Ecosystem System Services Concept and the 17 ecological services provided by healthy ecosystems to improve the ability of communities to remedy stressors that adversely affect the resilience of urban systems. The team developed a Sponge City Gradient, a Water Treatment Technologies Spectrum, and Six Adaptive Infrastructure Types.

Given the challenge of funding, political will, and complexity, the Plan operates evolutionarily through a set of Adaptive Infrastructure Types that are incremental, contextual, and successional. These value-added infrastructural retrofits—green streets, water treatment art parks, urban eco-farms, conservation neighborhoods, parking gardens, riparian corridor improvements, lake aerators, vegetative harvesters and floating bio-mats, and a city greenway—complement mainstream infrastructural investments. The approach builds a cityscape expressive of the city’s desire for a green stormwater utility that creates a place-based open space system.

The Sponge City Gradient formulates planning interfaces between land use characteristics and hydrology shaping the Framework Plan. Opportunities are configured according to prevailing development profiles shaping downtown, suburban, exurban, and rural sectors. Pixelation works within fragmented land-starved downtown landscapes. Nesting engages the pulsed frequencies of activity in parking lots and other large commercial sites. Clustering is an ideal pattern language for land-rich development. Connection in rural areas and along riparian corridors continues the imperative of large scale natural systems to connect.

The City has secured funding to implement demonstration projects of the city greenway and a new town square as a rain terrain. The town square site just completed brownfield mitigation and hydrological modeling through an EPA Brownfields Cleanup Grant in 2018, and development of the square is underway. The City adopted the Low Impact Development codes developed by the project team.