What’s The Largest Man-Made Lake In Hawaii

Waita Reservoir Hawaii
© Alexandre G. ROSA/Shutterstock.com

Written by Patrick Sather

Updated: May 31, 2023

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Located on the island of Kauai, Waita Reservoir is the largest man-made lake in Hawaii. This private freshwater reservoir overlooks the small unincorporated community of Koloa on the southern end of the island.  In total, Waita Reservoirs covers an area of 425 surface acres. This makes it slightly larger than the second-largest reservoir in the state, Lake Wilson, which measures 400 surface acres. Additionally, Waita reservoir also ranks as the overall second-largest Lake in the state after the 840-acre Hālaliʻi Lake. Sugarcane farmers originally built the reservoir in the early 1900s to supply water to their fields. Today, this private reservoir is best known as a popular fishing and sightseeing spot.

About Waita Reservoir

Waita Reservoir resides at a surface elevation of approximately 243 feet. Several small streams feed the reservoir, including Waihohonu Stream and Kuia Stream. No reliable data exists that provides the average or maximum depth of the lake. The lake measures around 4,000 feet long and 3,000 feet wide at its widest point. That said, it measures around 2,000 feet wide in most spots. In total, it features approximately 3 miles of shoreline. At max capacity, the reservoir can hold up to 9,900 acre-feet of water. 

Waita Reservoir continues to water local farmland via its 3-square-mile drainage area. That said, most people know the reservoir as a vibrant fishing and tourism spot. Many people come to the reservoir to catch fish, such as bass and tilapia. Local ATV tours often visit the area, and a zipline run by Koloa Zipline runs 2,500 feet across the reservoir. Other popular activities in the area include swimming, hiking, boating, kayaking, and canoeing. If you enjoy history, you can also easily walk from the reservoir to the nearby Old Koloa Sugar Mill or Kauai’s Tree Tunnel. 

Keep reading to learn more about the history and geography of Hawaii’s largest man-made reservoir. We’ll also cover reviews about the reservoir so can decide for yourself if you’d like to visit Waita Reservoir. 

History Of Waita Reservoir

Waita Reservoir Hawaii

Hawaii has very few natural lakes, but about 130 state-operated dams. The largest of these is Waita Reservoir.

©Alexandre G. ROSA/Shutterstock.com

Although Hawaii has hundreds of freshwater streams, it has very few natural lakes. In fact, you can find only five natural lakes across the entire state of Hawaii. For the native Hawaiians, this lack of natural lakes did not pose a significant problem. Native Hawaiians developed traditional farming practices that enabled them to produce the food they needed to survive. However, the arrival of European settlers in the late 18th century signaled a major shift in farming practices on the island. The Europeans brought with them new products and different techniques that required substantial changes to the environment of the islands. Suddenly, the lack of natural lakes on the islands represented a very significant problem. The islands’ new residents required manageable waterways to effectively irrigate their crops, including cash crops like sugarcane. This demand slowly built to a crescendo and kickstarted a variety of water projects across the islands.

Near the end of the 19th century, Hawaii’s farmers started building dams on river systems all over the islands. Within just a few decades, nearly 130 dams were built on Hawaii’s major islands. Most of these dams were constructed on private property to irrigate farmland for crops like sugarcane. One of these dams created the Waita Reservoir. Constructed in 1906, the Waita Reservoir Dam is 28-foot-high and 3,250-foot-long earthen dam. The reservoir was constructed to supply freshwater to nearby sugarcane fields. This sugar ultimately ended up at the nearby Koloa Sugar Mill, one of the first major sugarcane plantations in Hawaii. 

Waita Reservoir Geography

Na Pali Coast, Kauai, Hawaii.

The southern end of Kauai Island is where you’ll find Waita Reservoir.

©Shane Myers Photography/Shutterstock.com

Waita Reservoir is located at the southern end of Kauai Island. Hills surround the reservoir to the north, east, and west, while the Waita Reservoir Dam stretches across its southern end. Several small streams flow into the reservoir. The largest of these streams, Waihohonu Stream, flows into the western part of the reservoir.  

Kauai Island is the oldest of Hawaii’s main islands and consists of a giant, eroded shield volcano. The landscape around the reservoir features numerous rock formations formed by volcanic activity on the island. Moreover, Kauai is one of the wettest places on earth, receiving nearly 460 inches of rain each year. This rain fuels the large swaths of rainforest that grow across the island. Some of the trees that you can find around the reservoir include Hala, Puou, and ohia trees. You can also find native flowers, including hibiscus, orchids, and milkweed. 

The reservoir also supports numerous native and introduced animal species. The most common animals seen around the reservoir include feral cats, dogs, and pigs. That said, you may also see some of the island’s rare native animals. These include the Near Threatened Nene goose, the official state bird of Hawaii. Within the reservoir itself, you can find several species of game fish, including tilapia, largemouth bass, and peacock bass

Waita Reservoir resides entirely on private property owned by the Grove Farm Company. You can access the reservoir via a dirt road that also leads to the Old Koloa Sugar Mill, located south of the reservoir. The small, unincorporated community of Koloa rests just to the southwest of the reservoir. Meanwhile, the picturesque Kauai Tree Tunnel is located just a mile north of the reservoir at the intersection of Hawaii Rout 50 and Routh 520. 

Waita Reservoir Reviews

Waita Reservoir is a little-known gem on Kauai. If you want to visit the reservoir, several tour groups schedule various activities for you to take advantage of. Fishing is one of the most popular activities on the lake. Several tour groups schedule fishing trips to the lake for a fee, so you’ll want to do your research to find a package that works for you. The lake is well-stocked with game fish like bass and tilapia and allows fishing from the shoreline and by boat. Additionally, the reservoir hosts Keiki Fishing at Koloa Plantation Days, an annual fishing event. Other popular recreation activities in the area include ATV tours or ziplining over the lake. 

That said, Waita Reservoir is on private land, which means it is not readily accessible to the public. You cannot simply visit the reservoir unless you go on a private tour group. This also means that the Waita Reservoir lacks public amenities commonly found at public reservoirs. There are no stores, public restrooms, or other amenities that you may be used to. Still, the reservoir offers amazing views and is well worth the visit if you decide to book a tour. 

Where Is Waita Reservoir Located On A Map?

Waita Reservoir is on the island of Kauai, near the Tree Tunnel and Old Koloa Suger Mill, on the southern side of the island. Hawaii is located in the central Pacific Ocean, about 2,000 miles southwest of the mainland, the continental United States. The Hawaiian island of Kaua’i is 72 miles northwest of the state’s capital Honolulu on the island of Oahu.

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