Grahamstown Dam facts for kids
Quick facts for kids Grahamstown Dam |
|
|---|---|
 Location of the Grahamstown Dam in
New South Wales |
|
| Country | Australia |
| Location | Ferodale, New South Wales |
| Coordinates | 32°44′S 151°49′E / 32.733°S 151.817°E |
| Purpose | Water supply |
| Status | Operational |
| Construction began | 1955 |
| Opening date | 1969 |
| Owner(s) | Hunter Water Corporation |
| Dam and spillways | |
| Type of dam | Embankment dam |
| Impounds | Off-stream |
| Height | 12 metres (39 ft) |
| Length | 4.8 km (3 mi) |
| Dam volume | 2,124 m3 (75,008 cu ft) |
| Spillways | 1 |
| Spillway type | Controlled labyrinth spillway and baffle chute |
| Spillway capacity | 800 cubic metres per second (28,000 cu ft/s) |
| Reservoir | |
| Creates | Grahamstown Lake |
| Total capacity | 190,000 megalitres (6,700×106 cu ft) |
| Catchment area | 97 km2 (37 sq mi) |
| Surface area | 2,460 ha (6,079 acres) |
| Website at hunterwater.com.au |
|
The Grahamstown Dam is a very important dam in New South Wales, Australia. It's a special type of dam called an off-stream dam. This means it doesn't block a river directly. Instead, it stores water that is pumped into it from the Williams River.
This dam is located near Newcastle in the Lower Hunter Region. Its main job is to provide drinking water for the Hunter region. In fact, it supplies about 40% of the clean water for the area! It's the biggest dam for drinking water in the Hunter region. The large lake formed by the dam is called Grahamstown Lake.
Where is Grahamstown Dam?
Grahamstown Dam is very close to the town of Raymond Terrace. It's less than 4 kilometers (about 2.5 miles) from the center of Raymond Terrace.
Building the dam started in 1955. It was finished in 1965, and it began supplying water in 1969. However, water was first used from it in 1960 during a big drought.
The dam gets most of its water from the Williams River. Water is pumped from the river, past the Seaham Weir, into the dam. This pumping happens through the Balickera Canal and a special pumping station. Other pumping stations, like Campvale and George Schroder, help move water from the dam to the water treatment plant. This plant cleans the water before it goes to homes.
The dam was built by the NSW Water Conservation and Irrigation Commission. They built it for the Hunter Water Corporation. Their goal was to make sure the Hunter Region had enough water.
How Grahamstown Dam is Built
The dam wall is made of earth. It's about 12 meters (39 feet) high and an amazing 4.8 kilometers (3 miles) long! When the dam is full, it holds 190,000 megalitres of water. A megalitre is a huge amount, like a million liters!
The lake itself, Grahamstown Lake, covers a large area of about 2,460 hectares (6,080 acres). The area that naturally collects water for the dam (its catchment area) is quite small, only 97 square kilometers (37 square miles).
The dam has a special overflow system called a "labyrinth spillway." This spillway can release a lot of water very quickly if needed, about 800 cubic meters (28,250 cubic feet) of water per second.
Dam Improvements Over Time
Since Grahamstown Dam was first built, it has been made even better with several important upgrades:
- 1973: A special layer of bentonite clay was added inside the dam wall. This clay layer is like a super-strong seal, making sure no water leaks through. It's over 2 kilometers (1.2 miles) long and about 21 meters (70 feet) deep on average.
- 1985: The "Full Supply Level" of the dam was temporarily lowered. This was done to help protect the dam wall from damage if there were very big floods.
- 1994: More work was done on the clay core, extending it up to the road level along the entire dam wall. Also, rocks were added to the outside of the main dam wall to make it even stronger.
- 2005: The Full Supply Level was increased again. This made the dam able to hold 50% more water! This was possible because a new spillway was built and a new channel was made under the Pacific Highway to help water flow out safely.
