Reviews of Current Knowledge - ROCKs

Our ROCKs provider unbiased science-based information in a readable format. They focus on water-environment topics of general interest. Our policy is continually to revise and add to these ROCKs.

Sewage Sludge: Operational and Environmental Issues

FR/R0001  | Summary | V4 June 2016

Sewage sludge is an inevitable consequence of sewage treatment. The quantity produced has increased because of regulations requiring additional standards of treatment and because of increasing population. The various ways in which it can be treated, used or disposed of are discussed as well as the measures that can be taken to ensure no adverse environmental or health effects.

Eutrophication of Freshwaters

FR/R0002  | Summary | V2 August 2006

Eutrophication is the enrichment of natural waters with plant nutrients, largely derived from man’s activities. This disturbs the balance of aquatic life and results in poor water quality. The review explains the causes of eutrophication, the various impacts, and the legislation and initiatives that are being used to control the problem.

Endocrine Disrupters in the Environment

FR/R0003 | Summary | V3 May 2011

Endocrine disrupters are chemicals that may interfere with hormone systems. Some effects have been seen in certain marine and freshwater organisms, such as fish downstream of sewage treatment works. The review explains what endocrine disruption is and which chemicals have been questioned. There is a discussion of the risks for the environment and for human health compared with other commonly encountered risks.

Legionella in the Environment

FR/R0004 | Summary | September 2001

Legionellae are rod-shaped bacteria that can cause Legionnaire’s disease, an acute form of pneumonia. They occur naturally in fresh water, sea water and moist natural environments throughout the world. They prefer warm water, hence most outbreaks of Legionnaire’s disease are associated with cooling towers, evaporative condensers, hot and cold water systems and spa pools. The review explains the growth of the bacteria in water systems, the maintenance factors affecting colonisation of cooling water systems and the efficiency of biocides and other control agents.

Cryptosporidium in Water Supplies

FR/R0005 | Summary | V3 December 2011

Cryptosporidium is a waterborne parasite, which can cause an unpleasant illness called cryptosporidiosis. The symptoms are diarrhoea, mild abdominal pain, nausea, vomiting, mild fever and fatigue. Outbreaks of cryptosporidiosis have been caused by poor hygiene, contact with farm animals, contaminated drinking water and contaminated swimming pools. The review summarises the incidence and principal causes of the disease, and the measures employed by UK water suppliers to prevent infection via the water supply route.

Giardia in Water Supplies

FR/R0006 | Summary | V2 October 2012

Like Cryptosporidium, Giardia is a parasite, which can cause an unpleasant illness referred to as giardiasis. The symptoms are acute diarrhoea, abdominal cramps, bloating and excessive flatulence. Outbreaks have been caused by contact with farm animals, contaminated drinking water, contaminated food and contaminated swimming pools and other recreational waters (rivers and lakes). The review summarises the incidence and principal causes of the disease, and the measures employed by water suppliers in the UK to prevent infection via the water supply route.

Causes of Copper Corrosion in Plumbing Systems

FR/R0007 | Summary | V3 September 2017

The aim of this review is to assist practitioners to diagnose the many different types of corrosion failures, which can occur in copper plumbing systems and help to avoid them occurring. It is not meant to be a substitute for expert opinion in serious cases. It outlines failures which can occur in both hot and cold domestic water systems (not closed central hearing systems) and describes many different types of copper corrosion, covering manifestation, cause and how they can be avoided.

Water and the Water Environment: a summary of UK legislation and agreements

FR/R0008 | Summary | August 2003

As a consequence of subsequent and more recent legislative changes this Rock has now been withdrawn. It remains obtainable by special request.

Cyanobacterial Toxins in the Water Environment

FR/R0009  | Summary | V2 January 2014

Cyanobacteria (blue-green algae) are natural inhabitants of fresh, brackish and marine waters and are of worldwide distribution. They produce a diverse range of small molecules (cyanobacterial toxins: cyanotoxins) which are hazardous to human and animal health. The sources and properties of these toxins are briefly reviewed. Examples of the adverse effects on human health, domestic animals and wildlife are given. Reactive and proactive measures and further needs in this context are presented. The reduction of cyanotoxin problems in natural and controlled waters as a potential benefit of eutrophication control is also discussed.

Household Chemicals and the Water Environment

FR/R0010 | Summary | V2 December 2012

We all use chemicals in the home and in gardens. Some chemicals, such as cleaning agents and detergents, may be discharged directly and legitimately to the drains and hence enter water bodies. Others, such as paints, solvents or surplus pesticides, may be disposed of with little consideration for the environment, and may pose a risk, especially in the long term. This review considers the risks that household chemicals pose to the aquatic environment and the means of controlling these risks.

Urban Drainage and the Water Environment: a Sustainable Future

FR/R0011 | Summary | V2 April 2013

This review describes how drainage systems in urban areas developed in order to understand how we have got to where we are today and how systems can be developed to cope with increasing urban populations and changing weather in the future. It covers the issues concerned, including sustainability. If it all goes downthe drain, it has to be pumped and treated. Handled appropriately, surface water could be a less expensive alternative than opening new resources when weather stresses the existing ones.

World Water: Resources, Usage and the Role of Man-Made Reservoirs

FR/R0012 | Summary | V3 May 2019

This review addresses man-made reservoirs that provide water storage and other benefits such as hydroelectric power, flood control and navigation. In many areas the life span of reservoirs is determined by the rate of sedimentation, which gradually reduces storage capacity and eventually destroys the ability to provide water and power. This review considers overall water resources and usage, the world stock of reservoirs, the problem of sedimentation and possible measures to minimise the impact of sedimentation.

Desalination for Water Supply

FR/R0013 | Summary | V3 June 2015

The scarcity of existing fresh water supplies is becoming a problem in many parts of the world. In some areas a process called "desalination” is used to reduce the salt content of brackish and sea waters to turn them into a drinkable supply. This review explains what makes a water drinkable, the various processes used for desalination and their costs compared with the costs of conventional water supplies.

Surface Water Management and Urban Green Infrastructure - A review of potential benefits and UK and international practices

FR/R0014 | Summary | May 2011

This ROCK, which has about 200 references, considers the breadth of benefits that urban green infrastructure can play for managing surface water with examples from many countries around the world where the authors have seen GI working and/or discussed it with people who have implemented GI for surface water management.

Floods: alleviation, protection, response and risk management

FR/R0015 | Summary | July 2011

Flooding is the most widespread of all natural hazards, often arising from adverse meteorological conditions such as:

The main factors which need to be considered regarding flooding include technical, social and governmental aspects. This ROCK aims to provide a concise description of these factors on a worldwide basis but with a more specific European and UK focus.

The role of water in the production of energy

FR/R0016 | Summary | V2 November 2016

This review is concerned with the role of water as one of the many sources of energy. Other major sources include solid fuels, oil, natural gas, nuclear, biofuels and waste, together with smaller contributions from geothermal, solar, wind and heat. Hydropower, power from water, makes a relatively small contribution towards the overall provision of worldwide energy. By far the largest energy supplies come from solid fuels, oil and natural gas. Hydropower, however, plays a more significant role in the direct provision of electrical energy, 16% of the total world production in 2010.

Water for Food Security

FR/R0017 | Summary | December 2013

Water and food are inextricably linked as significant quantities of water are required to produce our food. Water is fundamental to agricultural production: crops require water to grow; livestock require water for drinking and hygiene; and farms need water for operations and processing. Inland fisheries and aquaculture cannot exist without freshwater. The water consumed in food production is either sourced directly from precipitation or from soil moisture (green water), or withdrawn from aquifers, streams and lakes (blue water).

The Measurement of Free Surface Flows

FR/R0018 | Summary | January 2013

Hydrometry embraces the measurement of all the elements in the hydrological cycle including surface water flows, groundwater movement and associated phenomenon such as sediment movement and morphology. This ROCK concentrates on a major element within hydrometry, namely the measurement of free surface flows. It does not cover flows in closed conduits and pipes although some of the methods described can be used for these applications.

Hard SuDS Infrastructure in the Urban Environment

FR/R0019 | Summary | June 2014

This ROCK focuses on hard Sustainable Drainage (SuDS) infrastructure, particularly pervious paving systems (PPS), infiltration trenches and rainwater harvesting, discussing their role in the “SuDS triangle”; also covered are the ways in which they can mitigate and adapt to climate change, and address the Urban Heat Island Effect.

Demystifying Natural Water Retention Measures (NWRM)

FR/R0020 | Summary | September 2014
This review aims to clarify the competing definitions of NWRM and to scope where these measures fit in the context of the Water Framework Directive, other related policies and regulations, and climate change policy. It will outline what the key measures are and will provide some understanding of their evaluation for assessing the technical and economic potential of NWRMs in the UK and elsewhere in the EU. Winner of the David Newsome Award 2013.

Community Involvement in UK Catchment Management

FR/R0021 | Summary | January 2015

This Review of Current Knowledge (ROCK) highlights issues related to monitoring and understanding the complexity of river catchments which are subject to multiple pressures. It details how countries, such as the UK, are beginning to manage catchments on a local level with involvement of local people. Case studies are also presented to emphasise how we are now within exciting times due to the rapid growth in technology and communication facilities, which can and should be utilised in innovative ways (and to our advantage) to support the management of river systems.

Sediments in the Fresh Water Environment

FR/R0022 | Summary | March 2015

This review of current knowledge (ROCK) is concerned with the movement of sediments in the freshwater environment, an important subject but a very complex one. The ROCK provides an outline of the subject and a description of some of the principles used in the analysis of the many complex processes. However, for details of the analytical methods it is necessary to consult major text books on the subject.

Smart Meters and Domestic Water Usage

FR/R0023 | Summary | May 2015

This review aims to create a more coherent and integrated understanding of how water metering, through smart meters in particular, can affect domestic demand for water. It also considers the influence of additional factors that serve to shape the effectiveness of metering technologies. It is important to note that the contextual and governance focus of this review, whilst centred on the UK, does draw upon research and information that is more global in scope. Winner Winner of the David Newsome Award 2014.

Water Reuse

FR/R0024 | Summary | September 2016

This Review sets out the facts (and perceptions) and aims to clarify some of the most common questions that people have about ‘water reuse’. It explains the differences between the very small scale and very large scale schemes, the differences between reuse to create non-potable and drinking water, the types of technology used, actual and perceptions of risk, how reuse schemes are regulated and risks managed and finally, an explanation of the energy and other resource requirements of reuse and the implications of these on cost.

Sediments in the Marine Environment

FR/R0025 | Summary | November 2016

This review is concerned with the movement of sediments in the marine environment. This is an important subject with influence on all nations with a coastline. The review provides an outline of the subject and a description of some of the methods used in the analysis of the many complex processes. However, for details of the analytical methods it is necessary to consult major text books on the subject.

Climate Change. The Fundamentals

FR/R0026 | Summary | March 2017

The subjects of climate and climate change are enormous and embrace many scientific disciplines. This review seeks to deal solely with the scientific evidence and is based heavily on the work of the Intergovernmental Panel on Climate Change (IPCC). The review sifts some of the more important fundamental issues and provides a bibliography for those wishing to take the subject further.

Microplastics in the Freshwater Environment

FR/R0027 | Summary | October 2017

With ever-increasing quantities of plastic being manufactured and ending up in the environment, understanding the consequences of this will be critical to ensure the protection of ecosystems and freshwater resources. This review looks at the sources, abundance, transport, behaviour, fate, associations with chemicals, and ecological consequences of microplastics once they reach freshwater systems. There are many questions which remain to be answered and it is therefore a priority area for future research.

Flood Mitigation

FR/R0028 | Summary | January 2018

In 2011 FWR published a review (ROCK FR/R0015) entitled ’Floods, alleviation, protection, response and risk management’, that was wide ranging and provided a concise description of the main factors which need to be considered regarding flooding. The purpose of this current review is to focus more closely on flood mitigation, including resistance and resilience, accepting that absolute protection against all future flood events cannot be guaranteed.

Freshwater Pollution: Ecological Impact Assessment and Remediation

FR/R0029 | Summary | November 2018

Pollutants can impact organisms either directly by depleting oxygen levels for example, or indirectly by altering the ecosystem in which they live. This Review deals with:

Plastic Pollution in Rivers and Oceans

FR/R0030 | Summary | November 2018

The presence of waste plastic in the surface water environment has developed into a serious problem. It is not only unpleasant, but is a threat to sea birds, aquatic mammals, fish and ultimately to human health. The topic has captured the media and public interest. Among this avalanche of media concern, this ROCK seeks to explore the present problem in the surface waters of the planet and to review information on our behaviour and potential solutions.

Climate Change Impacts: River, Coastal and Urban Infrastructure

FR/R0031 | Summary | April 2020

The presence of waste plastic in the surface water environment has developed into a serious problem. It is not only unpleasant, but is a threat to sea birds, aquatic mammals, fish and ultimately to human health. The topic has captured the media and public interest. Among this avalanche of media concern, this ROCK seeks to explore the present problem in the surface waters of the planet and to review information on our behaviour and potential solutions.

Circular Economy in the Water Sector

FR/R0032 | Summary | December 2020

The circular economy is an economic strategy based on minimising the production of waste and recycling material resources utilised in economic activity. This review describes the circular economy and how it relates to the water industry. It has been structured to explain: