1. Introduction

The Greater Golden Horseshoe is forecast to grow to 13.5 million people and nearly 6.3 million jobs by 2041, making it one of the fastest-growing city-regions in North America.[1] In planning for and managing growth, the province and municipalities need reliable information on the capacity and constraints of servicing infrastructure in the region.

The project was conceived in three phases with the ultimate goal of achieving a better understanding of the capacity of water and wastewater infrastructure in the Greater Golden Horseshoe, as well as the availability of fresh water and the assimilative capacity of the region's "inland" water systems (that is, systems other than the Great Lakes), including lakes, rivers, and aquifers.

Phase 1: Feasibility study to answer two questions:

• What data are available to assess the capacity of and constraints on existing and planned water and wastewater systems relative to the availability of fresh water and the assimilative capacity of the region's inland water systems?
• Using the available data, what types of data products and tools can be developed to better inform the allocation of growth across the Greater Golden Horseshoe?

Phase 2: Data collection and analysis and build-out of spatial database.

Phase 3: Design and build-out of scenario-based decision-support tool to identify environmental and infrastructural vulnerabilities across the Greater Golden Horseshoe.

Deliverables from each phase of the project are intended to inform the implementation of the Provincial Policy Statement, 2014, and of the Growth Plan for the Greater Golden Horseshoe, 2017. For example, the Growth Plan includes policies to ensure that "sustainable water and wastewater services are available to support future growth."[2] This study will also contribute to the implementation of the Greenbelt Plan, 2017, which contains policies for growth in small towns, villages, and hamlets within the Greenbelt and for protecting water resources across the region.[3]

Ideally, the resulting information and assessment tool can be used to guide population growth allocations, first by the Province and then by upper- and single-tier municipalities across the Greater Golden Horseshoe, to reduce pressure on areas with environmental vulnerabilities and constraints on infrastructure, including financial constraints.

In the early 1990s, the Province of Ontario undertook a similar exercise to the current feasibility study. Then too, the focus was on the need to develop a better information and modelling framework for managing growth:

The pressures for significant growth in parts of Southern Ontario are providing major challenges for local governments. The potential feasibility and costs of providing water and sewer servicing schemes are of particular interest. As a consequence, an interministerial Committee was established to review the existing situation and to provide recommendations for alternate strategies to accommodate predicted growth through schemes which will not only be environmentally appropriate but which are technically and economically feasible.^[4]