Knowledgebase Collection

Integrated Water Resource Management

Integrated Water Resource Management (IWRM), also known as One Water, is an approach to managing water that looks holistically at the planning and management of water supply, wastewater, and stormwater systems.  IWRM focuses on the water cycle as a single connected system and promotes coordinated development and management of water, land, and related resources to maximize the economic and social benefits while minimizing impacts on the environment.

From this page, you can search for resources that provide background, and policy guidance on integrated water resource management, as well as examples of regulations, reports, and  functional plans. And you can filter these search results by resource type and various geographic characteristics.

APA Resources


This policy guide recognizes the importance of water as a central and essential organizing element in the built environment. It addresses the importance of ensuring that land-use, environmental and infrastructure planning for water will increase resilience to extreme events and climate change.

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This PAS report focuses on the One Water paradigm, which advances management of water supply, water quality, and stormwater as a single resource. It includes strategies that planners can use to integrate water issues into their work.

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This edition of PAS Memo explores the challenges and opportunities associated with integrated urban water management and addresses the need for cooperation and leadership between urban planners and water service personnel.

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This edition of PAS QuickNotes introduces the One Water concept and discusses water conservation strategies.

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This JAPA article reviews the Dutch and European trends in water management and identifies four potential approaches to integrating water management and spatial planning in the Netherlands or elsewhere, depending on the adoption of a regulatory or strategic approach in planning.

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Deep Trouble

This Planning article explains the water crisis in Flint, Michigan and considers the role planners have in solving it.

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The Tricky Business of On-Site Water Treatment and Reuse

This Planning article introduces the concept of on-site water treatment and reuse and dispells some common myths about the practice.

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In China, Rethinking a Resource

This Planning article looks to China's Sichuan Province for an example of successful water resource management.

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Zoning, Takings and Water Resources

This APA Learn course includes a discussion on the Murr v. Wisconsin Supreme Court ruling and how to apply the ruling's principles to zoning and environmental regulations.

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Comprehensive Planning and Green Stormwater Infrastructure

This APA Learn course explores how green stormwater infrastructure projects can be incorporated into comprehensive planning to conserve resources, beautify neighborhoods, and enhance public spaces.

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Linking Water and Land-Use Planning

This APA Learn course highlights state legislative initiatives that link water and land-use management to promote communities that are water resilient.

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Water Decision-Support Tools for Planners

This APA Learn course highlights several tools integrating land-based planning and water management including geospatial modeling, web-based visualizations, senario-based projections.

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Water- and Land-use Planning Relationships

This APA Learn course explores the complex relationship between water- and land- use by discussing the results of several research projects.

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Planning for Water

This APA Learn course reviews the integrated approach to planning and water resource management known as "One Water" and touches on the best practices and financing techniques.

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Water for Our Cities: A Collaborative Approach

This APA Learn course focuses on water resource management through watershed planning and how this approach is applied in the metropolitan areas of New York, Seattle, and San Francisco.

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Planning and Urban Water Management

This APA Learn course presents the results of two research projects supported by the Water Environment and Reuse Foundation and Water Research Foundation on the connection between land-use planning and water management.

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NOAA Water Resources for Planners

This APA Learn course highlights three key informational resources and tools that are provided by the National Oceanic and Atmospheric Administration (NOAA) to address water-related challenges.

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Meeting Water Needs: People and Environment

This APA Learn course examines three statewide water initiatives in Washington, Florida, and Ohio through the framework and implementation details of the "One Water" concept.

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Innovative Stormwater Management in Washington, DC

This APA Learn course explores the multiple strategies and stakeholders involved in responding to current and future water-related challenges in the National Capital Region.

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This report evaluates the link between water management and land use planning. It provides over 30 recommendations under six core theme areas and seeks to engage all planners in issues of water management.

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This "Tuesdays at APA" podcast provides a brief overview of One Water and discusses research efforts in the water supply and wastewater sectors to help communities move toward One Water.

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Lessons from the One Water Summit

This blog post discusses the main takeaways from the 2018 One Water Summit.

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Water: Cities' Biggest Risk?

This blog post considers the recent trend of naming water a top issue among planners and calls for unified action to address community concerns.

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NOAA Unveils New Water Resources Dashboard

This blog post introduces the NOAA's Water Resources Dashboard as a tool to be used when planning for environmental resilience.

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IWRM and the Water Cycle

Water exists in many forms—as lakes and rivers, glaciers and ice sheets, oceans and seas, underground aquifers, and vapor in the air and clouds. The water cycle (or hydrological cycle) describes the process through which water cycles in and out of the atmosphere – evaporating from the earth’s surface and falling again as precipitation.  As water falls, it collects in waterbodies, and recharges ground water supplies.  Urban development and the built environment impact the water cycle, altering patterns of drainage and runoff and affecting water quality and supply.

Traditionally, water supply, wastewater, and stormwater systems have been designed and managed separately. IWRM approaches the water-cycle as a single connected system and creates intentional linkages between water supply, wastewater, and stormwater systems and the utilities that manage them.  It also looks systematically at other areas that impact water systems, including land use patterns, agriculture, and energy.  

There are four central components of integrated water resource management: stormwater management, wastewater treatment, water supply, and conservation of existing water sources.

  • Water Supply - Water for human use comes from two primary sources—surface water and groundwater. Water supply systems convey, store, treat, and distribute water. Understanding water use helps to evaluate the effects of future development on water supply sources.
  • Wastewater Treatment - Wastewater is the byproduct household, industrial, and commercial uses of water. Wastewater management systems are designed to prevent waterborne pollutants from contaminating surface or groundwater sources. Increasingly, communities and wastewater utilities are beginning to view wastewater as a commodity with potential for resource recovery and reuse.
  • Stormwater Management – Stormwater runoff results from precipitation as it flows over land or impervious surfaces. Runoff includes pollutants and toxins that can impair waterways. Stormwater systems include traditional grey infrastructure, such as storm sewers, as well as green or nature-based infrastructure.
  • Conservation of existing water sources (Groundwater and source water) – Water conservation strategies are an important part of an IWRM approach. Water conservation measures address both indoor and outdoor water usage through regulations, education, outreach, and incentives.

IWRM and Planning

Water resources are impacted by decisions related to land use and growth management.  These decisions influence water demand, affect water supply, and impact water quality.  While planners have not traditionally worked directly on water and wastewater systems, they are often engaged in natural resources conservation and management, floodplain management, and green infrastructure projects. Increasingly, planners are working with collaboratively with water professionals and integrating water needs and challenges into local plans and regulations.

IWRM represents a paradigm shift in the management of water, both in terms of the physical systems that manage water and the institutional structures. Planners play a key role in facilitating implementation of IWRM efforts, which depend on interdisciplinary collaboration between water professionals, planners, engineers, landscape architects, public works professionals, and other related professions.

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