◢ Aralaganwila · Polonnaruwa District · North Central · Sri Lanka
A wide Mahaweli-era irrigation tank in the dry-zone plains near Aralaganwila - loved by locals for an evening dip and a glowing sunset, and known for the zig-zag triangular spillway that turns into a chain of little waterfalls when the reservoir is full.
About Pimburaththewa Lake
Pimburaththewa Lake - also written Pimburaththewa Wewa or Pimburattewa Tank - is a large irrigation reservoir near the town of Aralaganwila, in the Polonnaruwa District of the North Central Province. It lies roughly 32 km (about a 30-minute drive) from Polonnaruwa town, out where the ancient kingdom's green forest gives way to open paddy country.
Beautiful vistas of Polonnaruwa's lush greenery wrap the water - and it's a wonderful place to watch the sun go down.
The tank was built under the Mahaweli Development Project in the 1980s to supply water for farming around Aralaganwila, and today it doubles as one of the area's most-loved local bathing and picnic spots. It's quiet on weekdays and livelier on weekends and evenings, when families come down to cool off and catch the sunset.
The lake is at its most dramatic in the rainy season, when it fills and the spillway comes alive - but that is also when the water runs strongest, so a little caution goes a long way. And because this is open dry-zone country, wild elephants move through the area to drink, especially toward dusk.
History of Pimburaththewa
The Pimburaththewa reservoir you see today was developed in the 1980s as part of the Mahaweli Development Project - the vast state scheme that harnessed the Mahaweli Ganga, Sri Lanka's longest river, to bring water and farmland back to the dry zone. The tank stores irrigation water for the paddy fields around Aralaganwila, and its catchment ties into the neighbouring Maduru Oya system, whose national park was gazetted in 1983 to protect that catchment.
Its fame rests on one feature: a zig-zag spillway that turns a wall of overflowing water into a staircase of small falls.
That stepped, zig-zag spillway isn't just for show. By forcing overflow to wind down a longer, angled path, the design slows the water, spreads out its energy and protects the earthen bund from erosion - a neat piece of hydraulic thinking that also happens to be beautiful when the tank is full (around 2,400 acres at full supply).
The Mahaweli scheme was, in spirit, a revival of Sri Lanka's ancient tank-building tradition - the same dry-zone genius that produced the great reservoirs of Anuradhapura and Polonnaruwa. Some recent accounts go further and link Pimburaththewa itself to those ancient irrigation works; most established sources, though, describe the present tank and spillway as modern. Either way, it carries forward a very old idea: catch the rains, hold them, and let the land flourish.
Accounts of the lake's age differ: most sources describe a 1980s Mahaweli reservoir, while a few recent posts claim ancient origins. We've flagged both rather than treat the older-origin story as settled fact.
The signature spillway
What sets Pimburaththewa apart is its spillway - a striking zig-zag, multi-triangular spill structure built in the 1980s. When the tank is full and water is released, it tumbles down the angled steps like a chain of small waterfalls.
It isn't a true waterfall, but in full flow the spillway reads like a series of cascades - best enjoyed and photographed from a safe, dry vantage point well back from the moving water.
Getting to Pimburaththewa
The lake sits past Aralaganwila town, roughly 32 km and about 30 minutes from Polonnaruwa. The simplest approach is by road from Polonnaruwa, via Manampitiya and Aralaganwila.
By far the most practical way - a hired car, van or tuk-tuk from Polonnaruwa or Manampitiya. The final stretches are narrow rural roads, so drive slowly, especially near dusk when animals are about.
The tank sits close to the Maduru Oya dam and national park, so it pairs naturally with a safari or a dam visit - and with the Polonnaruwa ruins on the way out.
Distances to the lake are quoted differently by different sources - anywhere from about 32 km to 43 km depending on your start point and route - so allow a little extra time and use a map app for the final turns.
What to do at Pimburaththewa
First and foremost, Pimburaththewa is a swimming and bathing lake - a place locals come to cool off, picnic and watch the light. There are no formal watersport operators on the bund, so it's about simple water days done safely rather than organised activities.
The main reason to come. Wade and swim from the calm, shallow edges in daylight - the cool water is wonderful after the dry-zone heat. Read the Bathing & safety notes below first.
Spread out on the bund for golden hour - the sunsets here are the lake's signature. Bring a mat, snacks and water; weekends and evenings are the liveliest.
When the tank is full, the triangular spill runs like a chain of mini-falls - a unique photo subject. Shoot from a safe, dry vantage well back from the flow.
The water and forest edges draw dry-zone birdlife - egrets, eagles, kingfishers and more. Early morning is best; bring binoculars and a quiet manner.
Elephants and other animals move through to drink, especially at dusk. Watch only from a safe distance and never come between an animal and the water.
Pair your visit with a jeep safari in the adjoining Maduru Oya National Park, or a stop at the Maduru Oya dam, to round out a full dry-zone day.
Planning water activities? Bring your own gear - there are no rentals or lifeguards here - and treat it as wild, open water. The safety section below is worth a read before anyone gets in.
Bathing & safety
Pimburaththewa is a much-loved local bathing spot, but it's a working reservoir in wild, open country - not a managed swimming pool. A few sensible precautions keep a dip here safe and happy.
Wild elephants move through this area to drink, most often toward evening. Keep well back from the water's edge at dusk, and if any wildlife appears, leave the water calmly and give it a very wide berth.
The lake is most beautiful when it's full, but that's also when currents run strongest and the banks turn slippery. Bathe with extra care after rain, and never near the moving water of the spillway.
Reservoir beds shelve unevenly, with unseen drop-offs. Don't wade out of your depth, keep children close and in sight, and don't swim alone - there are no lifeguards here.
Swim in clear daylight and be out of the water well before dark. Low light hides hazards and is exactly when animals are most likely to come down to drink.
The triangular spillway looks photogenic, but flowing water over its steps is powerful and slick. Enjoy it from a dry vantage point - don't climb on or bathe near the spill itself.
This water irrigates the farms downstream and the area is shared with wildlife. Take your litter home, keep noise down, and avoid disturbing the banks and birdlife.
This section is general safety guidance for visitors, not a substitute for local advice - conditions change with the season, so ask people in Aralaganwila about the water before you swim.
Visiting with children
With the right care, Pimburaththewa can be a lovely family outing - paddling at the shallow edge, a picnic and a sunset. But this is wild, unmanaged water with no lifeguards, so children need close, constant supervision and a few firm rules.
Simple rules that matter
No swimming if any of these are true
Rule of thumb: if you'd hesitate at an unguarded river back home, treat Pimburaththewa the same way. In calm, shallow, daylight conditions with close supervision, it's a gentle spot for a family dip.
Latest update
A reservoir's water level, spill flow and access roads change constantly with the rains and with irrigation releases - so the single most useful habit is to check locally in Aralaganwila and heed any notices before you bathe.
This is general guidance gathered from public sources and last reviewed in early 2026, not a live conditions report - always follow the advice of local people and any on-site signs.
When to go
The dry zone is warm all year. The lake's mood swings with the rains, and the finest light is always at the end of the day.
The headline experience. Come in the last hour or two of daylight for cooler air, soft light over the water and Pimburaththewa's famous sunsets - then head off before dark.
After the rains the tank brims and the triangular spillway runs like a chain of little falls. It's the most spectacular time - but currents are stronger, so bathe with real care.
Between the rains the water is gentler and the rough access roads are easier going - a relaxed time for a quiet swim and a picnic, even if the spill is quieter.
Whenever you come, carry water and sun cover - there's little shade out on the bund - and keep an eye on the light so you're not caught at the lake after sunset.
Staying over
If you'd like to wake up beside the water, the Mahaweli Authority runs a holiday bungalow at Pimburaththewa. It's a simple, peaceful base for catching both sunset and the early-morning calm on the reservoir.
Bungalows like this are usually booked in advance through the Mahaweli Authority rather than on arrival, so plan ahead and confirm availability before you travel. Otherwise, Polonnaruwa town - about half an hour away - has the area's widest range of guesthouses and hotels.
Close by
Pimburaththewa sits in a corner of the dry zone rich with reservoirs, ruins and wildlife - easy to fold into a wider Polonnaruwa trip.
The big neighbouring park, known for elephants and its huge reservoir and dam - one of the best dry-zone safaris in this part of the island.
The UNESCO-listed medieval capital - Gal Vihara's rock Buddhas, the Vatadage and a sprawl of palaces and shrines. The region's headline sight.
A major Mahaweli dam and reservoir close to the tank, with sweeping water views and the ancient sluice discovered during its construction.
The local hub for food and supplies, and home to Aralaganwila Wewa and the ancient Silumini Seya on its eastern bank.
The revered Somawathiya Chaitya and its national park lie out across the dry-zone plains north of the Mahaweli - a peaceful pilgrimage and wildlife area.
The long Manampitiya bridge over Sri Lanka's greatest river - your crossing point on the way to the tank, and a scenic stop in its own right.
Find it
Pimburaththewa Lake, out past Aralaganwila in the Polonnaruwa District.
Photo gallery
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Watch
Short films from Pimburaththewa Lake and Aralaganwila.
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