Water Based
Quarry Restoration

 

 

 

 

Site Maintained by
Hafren Water

Discussion

 

Minutes of Steering Group Meeting - 6 February 2006

Minutes and Figures of Steering Group Meeting - 6 September 2006

Minutes and Figures of Steering Group Meeting - 30 November 2006

 

DISCUSSION AND GUIDANCE

A discussion is presented of the relationship between the site-specific constraints and strategic issues and decision-making.  A series of illustrated diagrams are presented giving design guidance for water-based quarry restoration in the following situations: riverside, sustainable development, ecology, site water management and agriculture.

Strategic overview

In order to facilitate the creation of large areas of specific habitat and undertake major flood alleviation or water resource schemes a strategic approach to planning is required, informed by relevant data, of which the hydrogeology forms a key component.  At present a reactive and ad hoc approach pertains with each Planning Application, often assessed in isolation.  NYCC is developing a more strategic approach, with targets set for restoration objectives.  These targets would relate directly to areas selected for inclusion within the mineral plan and maximise the benefits of a co-ordinated approach to quarry restoration.

 

A major part of the NYCC strategic overview of the current revision of mineral planning policy has been provided in the form of the Swale and Ure Washlands Mineral Site Afteruse Strategy which sets out the many issues to be considered and provides the regional context for the current research project.  The RSPB and EN are also understood to be taking a strategic look at habitat creation across the UK.

 

Linked to the targets in the UK BAP, objectives have been set by English Nature for each of 120 distinct Natural Areas.  These are intended to inform planning for habitat creation and management in Local BAPs or to provide more direct guidance where Local BAPs are yet to be prepared.  The Natural Area concept is a new way of looking at England that reflects the range of its ecological and physical characteristics (English Nature, Quarry Products Association and Silica & Moulding Sands Association, 1999).

 

Strategic planning could be applied at the scale of an individual Planning Application.  The tools are in place to do this through the development of regional and area action plans focussed on a particular area or issue.  Area action plans are due to commence at the end of 2008.

 

National biodiversity targets and local biodiversity targets will feed into the process.  However simply because a particular habitat is on the BAP list does not mean that it is necessarily useful or likely to be successful in a particular hydrological setting.

 

Stakeholder requirements

Different parties often want different things from a restoration, ie:

 

Industry generally wants to maximise mineral recovery and needs to maintain flexibility within the design whilst maintaining profitability.  Local public perception is also important to reduce objection to future Planning Applications.

             

Landowners have significant control over the restoration and often require some form of income generation subsequent to extraction.  This may be in the form of:

 

 

Long-term future income generation might be relatively small but is an important consideration for the landowner.

 

Local residents wish to minimise impact on their local environment and are often looking for increased amenity value within an acceptable time frame.

 

Nature conservationists wish to increase biodiversity and create areas of rare habitat.  In some cases this may require exclusion of the public from sensitive areas.

 

To meet the sometimes competing needs a multi-function end use may be a desirable objective and may incorporate:

 

 

However there will be a minimum size below which the desired objective will not be viable and disturbance/conflict may also be an issue with multiuse restoration.

Conservation -vs- other end uses

Several factors tend to push restorations towards conservation end use including the undoubted benefit for wildlife and the relative strength of the wildlife lobby.  Restoration for nature conservation is often seen as relatively uncontroversial, as opposed to more complex proposals which may delay or jeopardise planning permission which is not in a minerals company interest.  Final development of a site may occur under a separate Planning Application after mineral extraction and the proposed site restoration will therefore not be optimised for the final end use. 

 

Another factor is that often a landowner, although wishing to obtain income from a site, may not be familiar with the range of potential options.  Therefore, a ‘formal’ consideration of each afteruse option, perhaps linked to the regional strategic overview, may increase the range of quarry afteruse.  Councils could perhaps provide a range of potential end uses for sites in various locations that would be acceptable and encouraged.  Significant technical (ecological/ hydrological) input is required at a regional scale to provide guidance for restoration, which is otherwise beyond the scope of a site-specific restoration design.  The resources to provide this may lie with the Mineral Planning Authority and to some extent with the Environment Agency.  Nature conservation can be incorporated within most proposed restorations in conjunction with other end uses.  Involvement of the end user in the initial restoration planning is also greatly beneficial in optimising the restoration.  Regular meetings can then be used to modify the restoration scheme over time. 

 

Some sites could be entirely devoted to nature conservation, with creation of more specific habitat types appropriate to local priorities and of viable size, avoiding the creation of ‘parkland’.  Mineral operators may experience a difficulty with the public perception of ‘bare earth’ and the drive towards rapid ‘greening’ of restored areas, rather than perhaps longer term restoration required to establish more ‘difficult’ habitat.

 

Restoration size

Indications of the research project are that bigger is generally better, rather than the field-by-field approach currently in operation.  Large areas allow greater potential for strategic planning, larger (more viable) habitat creation and major works such as flood alleviation schemes.

 

However, negative public perception of large areas demarcated for extraction may lead to problems in obtaining planning permission.  In addition these large areas may contain in excess of the ~20-year resource usually incorporated within the minerals plan and permitted to the minerals operators.  Concentration of extraction in one area may also pose other problems with transport and distribution.  Multiple land ownership may also make matters more complex.  However, to employ planning strategy on a landscape scale, a method of meeting large-scale objectives is required.

Geographical Information System (GIS)

For strategic planning on a regional scale a GIS will prove a valuable tool for spatial analyses of data.  Scoping studies of using a GIS were performed as part of the Swale and Ure Washland project and within a pilot study of the Mendips (SRK, 2004).  Important factors to be incorporated into this may include depth to watertable and available fill material, although this data is often relatively site-specific.  Extraction could then be limited in areas with a high saturated mineral to fill ratio where the creation of open waterbodies is considered inappropriate. 

 

The RSPB has undertaken a GIS analysis to determine the most appropriate habitat creation objectives on a regional scale. The RSPB project set out to understand the contribution the minerals industry could make to UK BAP habitat creation targets, and to begin to address delivery of this potential contribution. A GIS database of active mineral sites was created and habitat creation experts built up a matrix of ecological parameters defining conditions under which each of 17 priority BAP habitats would be physically possible. A web-based (www.afterminerals.com) interactive mapping tool has been created. Each of the minerals sites has its own page showing the wildlife habitat or habitats that could be created there and why.

 

The results of the WBQR study indicate several factors as identified on the proforma datasheets that could be incorporated within a GIS system to assess a site’s potential for the range of water-based restorations and end uses identified.  Unfortunately local data is often unavailable and estimations must be made with regard to water levels and mineral thickness.  Often considerable data may rest with individual companies but not in the public domain.  Such things as mineral thickness would be considered confidential, but potentially groundwater and surface water monitoring data could be released to improve both the regional scale assessment and local hydrogeological assessments.  A central electronic archive of water level data would be extremely useful, perhaps developed from the on-going monitoring at most sites required by the MPA.

 

Income and costs associated with habitat creation

Landowners may be unaware of the potential revenue to be derived from habitat creation which could, under certain circumstances, exceed that which they could otherwise obtain from low-grade agricultural land.  However, obtaining appropriate funding can be complex and future funding is uncertain.

 

Restored sites have potential to be entered into Agri-environment schemes such as the High Level Stewardship Scheme sponsored by DEFRA to promote the creation/restoration of certain priority habitats.  The scheme is competitive and sites must demonstrate the potential to create and maintain worthwhile contributions to biodiversity.  Income is generated on a per hectare basis for qualifying habitat.  For example income to Nosterfield Nature Reserve was calculated for wet grassland (requiring annual inundation) at a rate of £360 per Ha, without flooding payments reduce to £80 per Ha.  The annual revenue derived from wet grassland was observed to increase from <£500 at water levels of 39 mAOD to >£5,000 at 41 mAOD.  In this case failure to obtain desired water levels will lead to a significant decrease in revenue.  Long-term funding and costs related to maintenance issues and the water environment should be a key consideration when optimising a site restoration strategy.

 

Restored waterbodies may provide a suitable opportunity to produce stock of native aquatic plants for habitat creation/restoration schemes. At present there are few, if any, large-scale growers of native wetland plants and conservation projects tend to rely on either (a) stock grown by non-specialist wholesale suppliers (often mis-named and of non-native provenance or including ornamental cultivars of native species), or (b) the efforts of small specialist nurseries which struggle to meet demand.

 

There is now a strong emphasis on using plant material (plants, rootstock or seeds) of locally- (or at least regionally-) native provenance but very few sources of supply.  Significant potential exists for revenue derived from this market, especially when large-scale habitat creation schemes are coming on line.

Water management plan

Mineral companies often have considerable land banks (freehold or leasehold) over which they have control or influence.  These include currently operational sites, restored areas, proposed future extraction areas and land which will never be worked.  An integrated approach to management of these areas will provide for an optimum site afteruse strategy.  A key part of this approach is a plan, re-assessed on an on-going basis, addressing water and ecological management alongside other operational issues and incorporating monitoring data from pre-operational phases through to final restoration.

 

On-going management of the water environment within a quarry restoration is considered key to the successful operation of a site.  A water management plan should be formulated containing pertinent data and it is envisaged that the site pro-forma datasheet could form the basis of this.  Target water levels (and durations) related to habitat goals would be included within the plan, together with water level control options related to the potential variations within local conditions. Items of income or expenditure related to variations in water level would be calculated and optimised.  These may include maintenance of habitat hectarage under a funding scheme, such as HLS, or reduction in maintenance costs for willow scrub removal.

 

Water control is an essential management tool on a nature reserve.  Maintenance of the watertable at the required level and with the necessary seasonal variability will allow the development of specific habitat.  A recurring problem is the encroachment of willow and other unwanted species which may be kept in check by seasonal flooding to a depth of approximately 10 cm during an 8-10 week period in January-February time. 

 

The cost and long-term importance of engineered control structures needs to be included in a management plan.  It may be that the initial capital outlay may be recouped over an acceptable period.  The cost benefit of the water management system and plan will frequently pass to the subsequent management of the restored area rather than to the quarry operator.

 

A potential valuable addendum to a site water management plan would be a restoration ‘closure’ report summarising the data for the site, eg rainfall, geology, water levels, fill material, which could be utilised for the subsequent afteruse of the site.  Data from the completed reports could perhaps enter the public domain and be incorporated within the regional spatial planning.

Schematic design guidance

A series of schematic drawings have been prepared to illustrate some of the findings of this study (see chapter 10)

In order to formulate a fully coherent end use, it is essential to fully understand the application site and its surrounding context.  This understanding is not restricted to the area’s ecological or mineral value, but includes such issues as recreational facilities both existing and proposed, economic opportunities, landscape setting, agri-environment, flood alleviation, and water resources.  Since these issues are not confined to the immediate vicinity of mineral sites, the “study area” for obtaining information to guide afteruse proposals may vary from the local parish, sized to a more regional scale.

 

By examining the significance and issues relating to various aspects of the landscape, opportunities may be identified for the minerals industry to contribute positively to the local landscape through changes to operations at the planning, working or afteruse stages of a site’s development.  Guidance developed from these opportunities may identify issues to be considered which contribute to biodiversity and enhance the local cultural heritage; and create a sustainable landscape for the future, and provide social and economic benefits to the people who live, work and spend their leisure time in the area.

 

The following schematic guidance notes are designed as a reference tool and are not intended to be prescriptive, but are flexible and should be used according to what is appropriate for each individual site.  The final restoration design should be compatible with national and local plans and policies such as the County Structure Plan, Minerals Local Plan, Biodiversity Action Plans and Planning Policy Guidance notes.