The Serpentine Dam is a major

water supply Water supply is the provision of water by public utilities, commercial organisations, community endeavors or by individuals, usually via a system of pumps and pipes. Public water supply systems are crucial to properly functioning societies. Thes ...

dam for

Perth Perth is the capital and largest city of the Australian state of Western Australia. It is the fourth most populous city in Australia and Oceania, with a population of 2.1 million (80% of the state) living in Greater Perth in 2020. Perth is ...

, Western Australia. The dam is used to store water that is released at a controlled rate to regulate the level in the

Serpentine Pipehead Dam The Serpentine Pipehead Dam was constructed to use the Serpentine River, in Western Australia, to convey water from Serpentine Dam to the interconnection with the metropolitan trunk main network. The dam is also used to store water from the D ...

reservoir, which in turn feeds water to the metropolitan trunk main network depending on demand. Construction of the dam was completed in 1961. The Serpentine Dam is one of the 15 dams, some of which have since been decommissioned, that have been built in

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

since the 1920s, along with the Serpentine Pipehead Dam. It was built as part of the Integrated Water Supply System (IWSS), the largest scheme currently managed by the

Water Corporation Water Corporation is the principal supplier of water, wastewater and drainage services throughout the state of Western Australia. It is the seventh successive agency to deal with the services in Perth, Western Australia. With offices in Perth ...

, which provides water for over two million people in Perth,

Mandurah Mandurah () is a coastal city in the Australian state of Western Australia, situated approximately south of the state capital, Perth. It is the state's second most populous city, with a population of 107,641 as of the 2021 Australian census, 2 ...

, and other Western Australian regions. Serpentine Dam is connected to the Serpentine Pipehead Dam, which stores water and desalinated water from the Serpentine Dam and other dams nearby for later use. The Serpentine Dam is an important water source because the

Perth metropolitan area The Perth metropolitan region or the Perth metropolitan area is the administrative area and geographical extent of the Western Australian capital city of Perth and its conurbation. It generally includes the coastal strip from Two Rocks in t ...

depends on it as a strategic water source, supplying on average per year, with an additional from the natural flows into the Serpentine Pipehead Dam. According to the Department of Water and Environmental Regulation, as of 2017 the Serpentine Dam alone has supplied about 4300 households with water annually since 2010.

History

There have been water supply shortage problems in Perth since the

Swan River Colony The Swan River Colony, also known as the Swan River Settlement, or just Swan River, was a British colony established in 1829 on the Swan River, in Western Australia. This initial settlement place on the Swan River was soon named Perth, and it ...

was declared on 2 May 1829. Only the wealthy at the time had rainwater tanks on their house roofs. Others obtained water through shallow wells supplied from the aforementioned rainwater tanks, though they were filled for only a few months annually. Several

swamps A swamp is a forested wetland.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Swamps are considered to be transition zones because both land and water play a role in ...

and

lakes A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much larger ...

and a few freshwater springs were also used as water sources. With these limited resources, water shortages occurred and the existing water sources became polluted over time. This caused the rapid spread of diseases such as

typhoid Typhoid fever, also known as typhoid, is a disease caused by '' Salmonella'' serotype Typhi bacteria. Symptoms vary from mild to severe, and usually begin six to 30 days after exposure. Often there is a gradual onset of a high fever over several ...

and

diphtheria Diphtheria is an infection caused by the bacterium '' Corynebacterium diphtheriae''. Most infections are asymptomatic or have a mild clinical course, but in some outbreaks more than 10% of those diagnosed with the disease may die. Signs and s ...

, especially among less fortunate people, and many became sick. In 1885, a Sanitation Commission was appointed by the Legislative Council. The first thing the Sanitation Commission did was to stop the use of

cesspits A cesspit (or cesspool or soak pit in some contexts) is a term with various meanings: it is used to describe either an underground holding tank (sealed at the bottom) or a soak pit (not sealed at the bottom). It can be used for the temporary co ...

and established four main drinking water supply sources; wells that were sunk into the ground, the roofs of houses and tanks preserving water,

Lake Monger Lake Monger ( nys, Keiermulu) is a large urban wetland on the Swan Coastal Plain in suburban Perth, Western Australia nestled between the suburbs of Leederville, Wembley and Glendalough. Located less than from the city of Perth and situated ...

, Smith's Lake, and other lagoons at the back of Perth, the rivers and brooks supplied from the

Darling Scarp The Darling Scarp, also referred to as the Darling Range or Darling Ranges, is a low escarpment running north–south to the east of the Swan Coastal Plain and Perth, Western Australia. The escarpment extends generally north of Bindoon, to th ...

. The Sanitation Commission also had plans to obtain a reliable pure drinking water source that would come from water that was piped from the Darling Scarp. These plans, however, fell through due to the projected cost of the project, risk of that water body being contaminated and unsanitary, and the idea seeming appropriate to only serve as local sources of water, not as a major water supply source. Perth civil engineers

Henry John Saunders Henry John Saunders (16 February 1855 – 13 October 1919) was an Australian engineer, businessman and politician. He was a prominent mining entrepreneur during the Western Australian gold rush and served on the Western Australian Legislativ ...

and James Barratt came up with a comprehensive plan for the city's first water supply scheme (Perth's First Water Supply Scheme) in May 1887. They proposed that water would be sourced from a dam on Munday Brook at Carmel and Canning Mills in the hills, covering an area of . They reported that the scheme was meant to have a storage capacity of up to of water and would be able to supply up to approximately 25,000 people. The combined population of Perth and Fremantle at the time was only 11,500 people, thus the scheme was to have the capability of supplying each person with about of water daily. This scheme proved to be significant as it paved the way for Perth to grow in response to the state's gold rush, and resolved the water supply shortage issues that they had been experiencing for over 50 years. South-West view across Serpentine Dam

Many dams have been built since the scheme's establishment, and it was an ancestor of all the different water supply schemes in Perth throughout the years, including the

Goldfields Water Supply Scheme The Goldfields Water Supply Scheme is a pipeline and dam project that delivers potable water from Mundaring Weir in Perth to communities in Western Australia's Eastern Goldfields, particularly Coolgardie and Kalgoorlie. The project was commi ...

and the Serpentine Scheme. The Serpentine Scheme eventually resulted in the construction of the Serpentine Dam between 1960–1961 and officially opening to the public in 1961.

Hydrography

The Serpentine Dam catchment is situated in the Darling Plateau within the Darling Scarp, on Kingsbury Drive, around south of

Jarrahdale, Western Australia Jarrahdale is a small historic town located 45 km south-east of Perth, Western Australia in the Darling Range. The name is derived from its situation in a jarrah forest. Established in the late 1800s as the state's first major timber milling ...

. It forms part of the

Archaean Shield A shield is a large area of exposed Precambrian crystalline igneous and high-grade metamorphic rocks that form tectonically stable areas. These rocks are older than 570 million years and sometimes date back to around 2 to 3.5 billion years. T ...

covered by open

woodland A woodland () is, in the broad sense, land covered with trees, or in a narrow sense, synonymous with wood (or in the U.S., the ''plurale tantum'' woods), a low-density forest forming open habitats with plenty of sunlight and limited shade (see ...

and private land areas that have been cleared for rural and

agricultural Agriculture or farming is the practice of cultivating Plant, plants and livestock. Agriculture was the key development in the rise of Sedentism, sedentary human civilization, whereby farming of Domestication, domesticated species created food ...

purposes. According to the Water Corporation, the Serpentine Dam can hold up to of water, has a wall height of at the lowest foundation and a reservoir length of . The catchment has an area of . The reservoir is at

Australian Height Datum The Australian Height Datum was introduced in 1971 as the official vertical datum for Australia, and thereby serves as the benchmark to which all height measurements are referred. The Australian Height Datum is an amalgamation of decades of spir ...

(AHD) and the highest point of the catchment, Mount Cuthbert is at AHD on the catchment’s east boundary, based on the Serpentine Dam Catchment Area Drinking Water Source Protection Plan (2007). Climatically, the area receives around of rainfall annually, most falling between May and September. Rainfall varies widely throughout the catchment, from rainfall isohyet in the east up to rainfall isohyet in the west.

Environmental issues

Streamflow decline

Climate change In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...

and rainfall declines have affected Western Australia for a long time, affecting water supplies around the area. According to the Department of Water and Environmental Regulation, the Serpentine Dam experienced a 16% drop in rainfall between 1961 and 2008, followed by a further 10% drop for 2008–2015 from the Bureau of Meteorology’s Karnet site. This caused streamflow into the dam to drop by 58%, nearly half between 1989 and 2008. In 2015, both the Serpentine Main and Pipehead dams' combined inflow were at an all-time low of just , for all the IWSS dams. This was an extremely low inflow rate compared to common flows of up to per annum before the mid 1970s, just around when the rainfall decline started. It is predicted that in the future, there will be around a 45% reduction in inflows, in the worst case scenario, up to 70% reduction, and even zero or near-zero inflow into the dams. In 2011, "water supplies in Perth and the South West... reached critically low levels after almost a year with no significant rain." The Water Corporation stated that Perth needed of water that year just to meet demand, otherwise restrictions would have to be enforced to households and industry to accommodate the city.

Bauxite mining

Most of the dam catchments that are connected to the IWSS are located in the south-western area of Western Australia.

Alcoa Alcoa Corporation (an acronym for Aluminum Company of America) is a Pittsburgh-based industrial corporation. It is the world's eighth-largest producer of aluminum. Alcoa conducts operations in 10 countries. Alcoa is a major producer of primary ...

has mined in these catchments to obtain

bauxite Bauxite is a sedimentary rock with a relatively high aluminium content. It is the world's main source of aluminium and gallium. Bauxite consists mostly of the aluminium minerals gibbsite (Al(OH)3), boehmite (γ-AlO(OH)) and diaspore (α-AlO(O ...

ore since 1963. The mining has significantly affected the northern

Jarrah forest Jarrah forest is tall open forest in which the dominant overstory tree is ''Eucalyptus marginata'' (jarrah). The ecosystem occurs only in the Southwest Botanical Province of Western Australia. It is most common in the biogeographic region named in ...

, including the Serpentine catchment as the mining process requires clearing forests, soil stripping in two layers, blasting of lateritic

duricrust Duricrust is a hard layer on or near the surface of soil. Duricrusts can range in thickness from a few millimeters or centimeters to several meters. It is a general term (not to be confused with duripan) for a zone of chemical precipitation and ...

and finally removal of broken duricrust with the underlying friable bauxite. The lost forest area is estimated to be replaced by 2032 as they have started to replant the lost forest area throughout the years with a prescription of 1300 tree stems per . Consequently annual inflow to the Serpentine Dam was projected to increase by 3.5% in 2011–2030, but decrease overall by 4.5% in 2030–2050.

Potential water quality risks

Pathogens In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ ...

are always a threat to water supply sources since they pose as a significant risk to public health, its effects on people range from illness up to even death, so water treatment regularly occurs in the Serpentine Dam catchment. Water treatment in the catchment can be directly affected by the land use activities that occur in and around the area. For example, off-road driving on unauthorised tracks contribute to

erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distin ...

in the area. Erosion affects the soil particles within the catchment and causes them to increase the

turbidity Turbidity is the cloudiness or haziness of a fluid caused by large numbers of individual particles that are generally invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of water quality. Fluids can ...

in the air. In turn, existing pathogens can adsorb these soil particles and can potentially resist disinfection better, thus increasing the risk of contamination of the water in the catchment. Other effects include the uprooting of vegetation, affecting plant growth, and smothering of riparian vegetation.

Land uses

Private land

There is approximately of private land in the south-east edge of the Serpentine Dam catchment. This private land is used for Tasmanian bluegum (''

Eucalyptus globulus ''Eucalyptus globulus'', commonly known as southern blue gum or blue gum, is a species of tall, evergreen tree endemic to southeastern Australia. This ''Eucalyptus'' species has mostly smooth bark, juvenile leaves that are whitish and waxy on ...

'') plantations, private dams, and some pasture and remnant native vegetation. In 2007, a large chunk of this land was sold to a Boddington Gold Mine (BGM) venture that planned to expand gold mines near Boddington disturbing the

State Forest A state forest or national forest is a forest that is administered or protected by some agency of a sovereign or federated state, or territory. Background The precise application of the terms vary by jurisdiction. For example: * In Australia, a ...

around the area. To get around this issue, BGM traded with the Department of Environment and Conservation other plots of land that had a similar size and conservation value to make up for the State Forest that would be disturbed from the BGM expansion project. This land eventually became Crown Land that would be managed by the

Department of Environment and Conservation (Western Australia) The Department of Environment and Conservation (DEC) was a department of the Government of Western Australia that was responsible for implementing the state's conservation and environment legislation and regulations. It was formed on 1 July 2006 ...

Crown land

The Serpentine Dam catchment lies within State Forests Number 14 and 67. The State Forests are managed by the Department of Environment and Conservation and currently used for nature conservation, recreation,

timber Lumber is wood that has been processed into dimensional lumber, including beams and planks or boards, a stage in the process of wood production. Lumber is mainly used for construction framing, as well as finishing (floors, wall panels, wi ...

production, and has many other purposes. Bauxite mining is also conducted in a part of the Crown Land in the catchment, the area in which the bauxite mining is done is planned to expand in the future. of the Crown Land is used for Frollett pine plantation in the north side of the catchment. The plantation is harvested when the time is right. Other uses for the Crown Land include the

Albany Highway Albany Highway links Western Australia's capital city Perth with its oldest settlement, Albany, on the state's south coast. The highway travels through the southern Wheatbelt and Great Southern regions, and is designated State Route ...

passing through the Serpentine catchment, and the Muja Northern Terminal Line, a major Western Power transmission line. also passes through the Serpentine catchment. The

Serpentine National Park The Serpentine National Park is a national park located on the Darling Scarp, approximately southeast of Perth in Western Australia. The depth of the falls has been undetermined, and is shrouded with conspiracy and enigmatism. Features and lo ...

is considered part of the catchment, being part of two-thirds of the Serpentine Pipehead Dam catchment.

Recreation

Recreation in the State forest and National Parks is managed by the Department of Environment and Conservation. The catchment has numerous

recreation Recreation is an activity of leisure, leisure being discretionary time. The "need to do something for recreation" is an essential element of human biology and psychology. Recreational activities are often done for enjoyment, amusement, or pleasur ...

activities like

hiking Hiking is a long, vigorous walk, usually on trails or footpaths in the countryside. Walking for pleasure developed in Europe during the eighteenth century.AMATO, JOSEPH A. "Mind over Foot: Romantic Walking and Rambling." In ''On Foot: A Histor ...

, which happens throughout the catchment, specifically along the

Bibbulmun Track The Bibbulmun Track is a long-distance walk trail in Western Australia. It runs from Kalamunda in the east of Perth to Albany, and is long. It is managed by government agencies, and has a foundation. It traverses the Darling Range and has i ...

which passes through the catchment around upstream of the Serpentine Dam. The area is home to the Monadnocks Campsite and the White Horse Hills Campsite. Other approved significant recreational activities include

orienteering Orienteering is a group of sports that require navigational skills using a map and compass to navigate from point to point in diverse and usually unfamiliar terrain whilst moving at speed. Participants are given a topographical map, usually a s ...

, rogaining,

picnicking A picnic is a meal taken outdoors ( ''al fresco'') as part of an excursion, especially in scenic surroundings, such as a park, lakeside, or other place affording an interesting view, or else in conjunction with a public event such as preceding ...

, and

mountain biking Mountain biking is a sport of riding bicycles off-road, often over rough terrain, usually using specially designed mountain bikes. Mountain bikes share similarities with other bikes but incorporate features designed to enhance durability and pe ...

. The Munda Biddi Mountain Bike Trail passes through the north of the Serpentine Dam catchment area. The Water Corporation operates a picnic area directly downstream of the Serpentine Dam catchment area. The Western Australian Endurance Riders Association (WAERA) have held annual horse-riding events in the north-west side of the catchment. The Darling 200 Rally run by the Light Car Club of WA Inc. under

Motorsport Australia Motorsport Australia, formerly the Confederation of Australian Motor Sport (CAMS), is the nationally recognised governing and sanctioning body for four-wheeled motorsport in Australia. It is affiliated with the Federation Internationale de l'Au ...

, previously known as the Confederation of Australian Motor Sport (CAMS) also used to regularly hold established motor events in the spring in the Serpentine catchment. Unauthorised activities include swimming, boating, and fishing.

Future

The Serpentine Dam is intended to go on supplying the Perth metropolitan area and other regions in Western Australia with drinking water. With the varying seasons and likelihood of drier years into the future from rainfall reduction due to climate change, and as demand increases, the government of Western Australia, along with landholders will need to consider developing additional water sources on top of the current existing IWSS dams to meet future water demands.

References

{{Reflist

External links

Dam storage level website

Sepentine Dam facilities brochure
Dams completed in 1961 Dams in Western Australia Shire of Serpentine-Jarrahdale