Introduction

The upper reaches of the Manchester Ship Canal (MSC) and associated dock basins have been polluted by operational discharges, surface water runoff as well as upstream inputs from the River Irwell. The resulting poor water quality has been exacerbated by the deep (7 m) water column and limited water exchange. In this chapter, we describe the water quality management strategies put in place since the late 1980s to address poor water quality, specifically oxygenation of the water column of the MSC and isolation of the docks from the canal followed by destratification of the water column and habitat diversification. We then examine the effectiveness of these strategies in improving water quality, increasing biodiversity and enhancing the recreational potential of the enclosed dock basins and the MSC.

Establishing an inland port at Manchester

Long before the Industrial Revolution in the late eighteenth century Manchester was already at the centre of numerous industrial settlements located in the foothills of the southwestern Pennines (Gray 1993). The success of local industry rendered the use of traditional transport such as pack-horses and horse-drawn carts inadequate to meet its needs, leading to the increased use of river navigation. The main navigable rivers are the Irwell and Mersey, although water shortages, siltation and mudbanks were obstacles to the reliable transport of goods (Gray 1993). Obstructions had already been cleared in the Mersey estuary to allow vessels to reach Bank Quay, Warrington, and it was suggested that clearing and dredging the Rivers Mersey and Irwell would enable vessels to proceed as far as Manchester (Gray 1993).