Nepean Dam is 82 metres high and 216 metres long with a catchment area measuring 320 square kilometres.

Located about 100 kilometres south of Sydney, Nepean Dam was the last and smallest of the four dams constructed to collect water from the Illawarra Plateau. Construction started in 1925 but stopped for two years during the Great Depression, before being completed in 1935.

Created by damming the Nepean River, Nepean Dam’s main role today is to supply water to the nearby towns of Bargo, Thirlmere, Picton and The Oaks, as well as the Macarthur and Prospect water filtration plants.

Today, you can walk across the dam wall, and soak up the Art Deco style of construction, which contrasts with the Egyptian influenced architecture of Avon and Cordeaux dams.

Nepean Dam is easily reached by taking the Bargo exit from the South Western Freeway (M5) then turn left onto Avon Dam Road. Facilities at the dam include picnic shelters, electric BBQs, drinking water, toilets and a children’s playground.

Visiting hours are 10am to 5pm daily (7pm on weekends and public holidays during daylight saving time).  There are no entry fees to any of our dams. Picnic areas cannot be reserved.

For educational excursions and project material, please contact our Education Office on: 02 4774 4435.

Top 5 things to see and do

1. Walk across the dam wall

To fully appreciate your picturesque surroundings, take a walk across the dam wall. It’s only 216 metres to the other end! Pause halfway and admire the views of the lake upstream. To better imagine how deep the lake is, cross to the other side of the wall and look down. You’re 82 metres above the ground!

2. Step back in time

Be on the lookout for reminders of the dam’s past as a favoured picnic spot in the 1930s and 1940s, when dams in the Upper Nepean would compete with each other for who had the most beautiful gardens. Enjoy the mixed plantings of European and native trees in a park-like picnic area along a terrace above the dam, and look out for a long line of Roman Cypress trees that follow the line of the spillway.

3. Soak up the views

Elevated paths and the dam wall provide impressive views of the lake in its natural bushland setting. Nepean Dam draws water from a 320 square kilometre catchment, the largest of the Upper Nepean dams. The Art Deco style of Nepean’s large concrete structures contrasts with the Egyptian style of Avon and Cordeaux dams. Look out for the concrete lined side spillway, which looks like a smaller version of the massive auxiliary spillway at Warragamba Dam.

4. Check out the environmental flows

Variable environmental flows from Nepean Dam and the other Upper Nepean dams mimic natural river flows and help sustain the downstream river environment. Look downstream from the dam wall for the environmental flows that are released all day, every day for the health of the downstream river.

5. Relax with a picnic

Relax with family and friends in the landscaped grounds. Throw down a rug and picnic under a shady tree or use one of our tables or shelter sheds. Electric barbeques, drinking water and toilet facilities are located throughout the grounds. There’s a children’s playground at the top picnic ground. Nearer the dam wall, a row of small timber picnic shelters with a log cabin-style feel run along the remnant platform from the temporary railway built during the dam’s construction.