The Mersey - a case history
[ Home ]

 

University Home Page

Site still Under Construction

This page is maintained by: Dr Rick Leah, Jones Building, School of Biological Sciences
Any feed back or comment would be welcome. Please email
NB: The HTML has not yet been 'verified' - apologies to any disabled users - I will try to attend to this during this academic year
Original material is Copyright University of Liverpool, 2003

The River Mersey and its Estuary

These notes are from two lectures for which the aim was to put into perspective many of the factors involved in management of FW and Estuarine ecosystems. This looks at a case study of the River Mersey and its Estuary to see how this system has been managed

First lecture will include an introduction to the river and its estuary and then we will look into the history of the Mersey and the subsequent laws that have been put in place for the management and rejuvenation of it. The history and laws are important to understand how the management protocol has progressed and the ideas can be applied to other situations.

The second lecture (not a seminar) will look more at the physical and biological properties of the Mersey Estuary, how some of the problems have been dealt with and how this has affected the biological diversity within the Mersey Estuary.

The River Mersey and its Estuary

(SLIDE of area - IN PREPARATION)

  • Although not totally a freshwater, estuaries have received a disproportionate level of perturbation.
  • Water flows into them before entering the sea and both marine and freshwater courses need to study the FW/Marine interface.
  • Mersey is a classic example of how not to treat the environment.
  • It has a well documented history and many studies have been undertaken to improve it.

Map of area and catchment - IN PREPARATION

  • Widely regarded as one of the most polluted estuaries in Europe —WHY?
  • Receives drainage from a huge catchment (5000 km2). Mersey rises in Peak District
  • Major connurbations of Manchester, Warrington/Widnes and Liverpool
  • Historically the area was the growth and development of the British Chemical Industry.
  • Was and still is a centre of manufacture
  • Major port and all the implications of spills
  • Huge increase in mersey basin population from 1700 to now (5+ million)

 

  • Widely regarded as one of the most polluted estuaries in Europe —WHY?
  • Receives drainage from a huge catchment (5000 km2). Mersey rises in Peak District
  • Major connurbations of Manchester, Warrington/Widnes and Liverpool
  • Historically the area was the growth and development of the British Chemical Industry.
  • Was and still is a centre of manufacture
  • Major port and all the implications of spills
  • Huge increase in mersey basin population from 1700 to now (5+ million)

Four sections of the estuary

Four sections of the estuary

Upper Estuary (Warrington to Runcorn)

  • Narrow winding channel widening briefly upstream of a sandstone ridge that constricts the river and allows Runcorn bridge

Inner estuary

  • Opens to large basin with extensive intertidal banks and salt marshes (supports huge numbers of migrant and local bird populations).
  • Banks are unstable and liable to erosion (South shore) and deposition (North shore)

The Narrows

  • Further downstream the geology forces the estuary into a straight, narrow but deep (30m at low water) gorge

Outer estuary

  • Large area of intertidal sand and mud
  • Two channels through this (The Crosby and Queens Channel) are maintained by dredging

Estuary shape

  • Important reason for the problems that have occurred as produces an unusual bottleneck effect
  • Has dramatic consequences for water flow
  • Retains water so flushing not high (water can stay for 30 days)
  • Narrow mouth produces high tidal velocity and strong scouring effects
  • High levels of suspended material due to current and scouring

Hydrography

Freshwater Inputs

Freshwater Inputs (SLIDE - - IN PREPARATION)

  • In Upper estuary main input is the Mersey river
  • In Inner estuary main input is the Manchester Ship canal

Upper estuary

  • Small volume of water means limited scope for dilution of polluted water coming from river
  • Coarse sand forms accreting sediments and the volume of the estuary is constantly decreasing
  • Finer material from rivers deposited in weak current areas or pass into bay as suspended material
  • Re-suspension of material occurs throughout estuary due to strong tides

Inner Estuary

  • Water channel meandering changes constantly as tonnes of material get shifted
  • Moving sediment acts as a source and sink of contaminants (locked up or released)

Overall

  • Large number of tributaries discharging into the Mersey which have received polluting inputs from a variety of anthropogenic sources along the water course as well as large input of pollutants directly into the estuary itself
  • We will look at some of these problems in more detail and context but need to start with an often neglected aspect of ecosystem management
  • How the problem arose i.e. the history
  • And political processes involved in the management ie The Regulatory Framework

History

  • Port of Liverpool Royal Charter 1207
  • Silting up of the Dee Estuary in 15th century caused a decline in trade at port of Chester and boosted Liverpool trade
  • 1700 population was 5000
  • First dock opened in 1715
  • Major factor in making Mersey catchment prime location for industrial expansion
  • Spinning and weaving mills were sited along waterways to get power for water wheels
  • Textiles: bleaching, dying and finishing all required huge amounts of water
  • Supporting industries manufacturing dyestuffs and chemicals sprang up along the transport waterways
  • Paper, heavy chemicals and glass production also flourished
  • 1801 population 78000
  • Rapid growth also attributed to huge trade links with Americas (mainly slave cargo) during the 18th century
  • Mersey south bank previously a day trip from Liverpool started to develop in 1815
  • Ships begun to be built here (famous Laird Shipbuilders)
  • Engineering works, fertiliser plants, sugar refineries, cement production and vegetable oil refineries developed
  • 1801 Birkenhead population 110 but 1851 = 24000
  • Lever Bros soap factory at Port Sunlight (1888) added to this
  • Not just local industry but Midlands (metals) and Pennine (textiles) used the area as a gateway to the international market
  • As a result Ellesmere Port and Stanlow area developed as Shropshire Union Cnal used to transport material from further afield
  • Warrington grew through the 19th century with Iron foundaries and tanning (effluent into the Mersey)
  • Widnes by 1900 large chemical works sited near the mersey and also disposing waste
  • Runcorn Castner-Kellner Alkali company produced caustic soda and chlorine by electrolysis of brine
  • 1926 nationwide merger formed ICI
  • Heavily polluted waters from Manchester further polluted by chemical industry at Widnes and Runcorn and sewage from Liverpool's growing population
  • Opening the Manchester ship canal deteriorated estuary quality further and caused salt marsh to dry up owing to the redirection of large amounts of water

Present Day

Land use patterns

  • North and East bank are urban and industrial
  • South and West shore lower reaches similar and upper reaches dominated by mudflats and salt marsh
  • Docks have reduced but carry more cargo than nearly ever before
  • But increased interest in using Mersey and docks for residential and leisure (marina)

RAMSAR map - - IN PREPARATION

  • Conservation status now 6700 hectares of 8900 total are SSSI
  • Internationally important numbers of wildfowl (>20000 overwintering) qualifies Mersey Estuary as Wetland of International Importance under the Ramsar Convention
  • Special Protection Area under EC Birds Directive
  • The Ramsar and SPA proposal covers the 6700 hectares of SSSI and gives better protection
  • Since recognising the gross pollution of the Mersey, regulation of pollution has played a pivotal process however many conflicting interests have arisen
  • Essential to obtain an understanding of the conflicting demands on the system (Biological, physical, political and sociological)
  • Only then can an informed, balanced and reasoned descision be made about its management

Regulatory Framework (its evolution and relevance to the Mersey)

  • First attended to in 1865
  • Queen Victoria appointed 3 commissioners who reported in 1869
  • Resulted in the Rivers Pollution Prevention Act 1876
  • RPA 1876 required Sewage discharges be inoffensive prior to discharge into inland waterways
  • Initially power to enforce was handed to local sanitary authorities
  • They were the main polluters so little happened until 1888
  • Passed to County Councils to enforce
  • Required sewage works to adopt new technology such as percolating filters and activated sludge
  • This development worked for domestic pollution but not the problem of industrial waste — no legal sanctions in place
  • Had to wait until after two World Wars and the Great Depression of 1929-1940 before The Rivers (Prevention of Pollution) Act 1951

The Rivers (Prevention of Pollution) Act 1951

  • New discharges of trade/sewage effluent to inland waters required a discharge consent
  • Limits set to nature, composition, temp. and volume of discharge
  • No poisonous, noxious or polluting matter allowed to enter river
  • Only applied to inland, not estuarine or coastal waters

Clean Rivers Act 1960

  • Extended requirements to include tidal and estuarine waters
  • But still only new discharges
  • Meant all of Liverpool's and Wirral's peninsula sewage escaped legislation
  • As well as the industrial discharge which had expanded since WWII
  • The Rivers (Prevention of Pollution) Act 1961
  • Extended the 1951 Act for all inland waters to old discharges
  • Mersey and Weaver River Authority 1965
  • Power to implement pollution prevention throughout the Mersey Basin
  • Effective for new discharges
  • Difficult with existing old discharges as Local Authorities reluctant to spend money and impose rates on local industry

Water Act 1973

  • Crucial for all pollution prevention measures (old and new)
  • Removed responsibility for disposal system from local authorities
  • Given to new independent Water Authorities
  • Not until

Control of Pollution Act (COPA) 1974

  • One of most significant
  • Covered all discharges (existing, new, inland, underground, tidal, coastal out to 3 mile limit)
  • Introduced public participation in decssion making
  • Allowed private prosecutions against companies
  • Took 10 years to be implemented as government worries about economic costs
  • Meant it wasn't until 1985 that all discharges into the Mersey came under full legal control

Present Day Local / National Regulation and Action

North West Water Authority

  • Since 1985 have established a strategy for bringing regions water to acceptable conditions
  • First step was via public consultations which established Water Quality Objectives
  • Using 4 point subjective scheme based on biological, aesthetic and chemical quality
  • Good, Fair, Poor and Bad
  • Mersey is predominately Poor and Bad (Warrington)

Objectives

  • To improve quality of all classified water courses in region to Fair by 2010
  • Upgrade existing Fair to Good (Mersey Channel off New Brighton)
  • All parts of estuary to maintain minimum of 10% dissolved O2 saturation at all times
  • 4. Beaches and foreshores not to be fouled by crude sewage or solid industrial waste
  • In addition since 1st Feb 1996 been required to promote the efficient use of water by customers through education, new technology and tariffs

1985 Mersey Basin Campaign (MBC)

  • Following national attention through Toxteth Riots (1981) problems including pollution highlighted
  • Direct involvement by the then Secretary of State (Heseltine) resulted in creation MBC
  • Aims to harness efforts of public authorities, private investors and voluntary organisations to revitalise the area
  • Concentrating on water quality and bankside redevelopment
  • £4 billion, 25 year program

National / International Legislation relating to the Mersey

  • Since joining the EEC (now EU) legislation taken on new dimension through:

European Community Directives

  • These establish emission standards for things like air quality, effluent discharge etc. through Environmental Quality Standards (EQS)
  • EQS are defined as
  • The conc. Of a substance in receiving waters must not exceed this standard if water to be used for a particular purpose or to achieve certain level of protection for aquatic life
  • Mersey Estuary has two areas where EQS apply
  • Bathing Waters EQS for bacteriological and sanitary parameters e.g. faecal coliforms
  • Dangerous substances EQS for substances on the basis of toxicity, persistence and bioaccumulation
  • Regulatory Authorities NRA (EA) formed to enforce standards under EPA 1990
  • Environmental Protection Act 1990
  • Part 1 introduced Integrated Pollution Control (IPC)
  • Enforced by Her Majesty's Inspectorate of Pollution (HMIP)
  • Objectives of IPC:
  • Prevent/minimise release of prescibed substances and to render harmless any substances which are released
  • Develop an approach to pollution control based on the processes source and considers industrial discharge in context of effect on whole environment

Further Developments Spurred on by EU Standards

Urban Waste Water Treatment Directive 1991

  • Set out minimum treatment standards for sewage discharge throughout EU
  • For Mersey — all existing sewage has to receive secondary treatment by 2000

Integrated Pollution Prevention Control 1993

  • Is a proposal from EC Commission
  • Aimed at preventing and reducing pollution from existing industrial installations (similar to IPC of UK)
  • Main improvement — traditionally looked at air, water and land emissions separately
  • This directive aims to provide integrated approach to achieve high level of protection for the environment and human health as a whole.
[../../footer.htm]