Puttenahalli Lake

JP Nagar, 7th Phase

Brief

Puttenahalli lake is a Type-C rainfed 13 acres 25 guntas lake located in JP nagar 7th phase between Brigade millenuium and L&T South City apartments. Currently the lake has a public access and is surrounded by 100+ slum dwellings. It has a constructed wetland and a water spread area. The depth of the lake varies from 6ft to 18ft with an undulating clayey surface. The lake is fenced on all sides. The Puttenahalli neighborhood lake improvement trust (PNLIT) is responsible for maintaining the health and activities around the lake.

Inflow

The lake has 4+2 storm water inlets and one 100mm PVC partiallytreated water inlet which lets an inflow of 4.5lakh liters of water per day from the south city apartments. The 4 Storm water inlets are let into the wetland and are functional only during the rainy season. They are hume pipes of 300 mm dia each. Inlet volume unknown as the water drains in from the road and rooftops of the neighboring homes. There is one non functioning 300mm inlet to the water spread and a fully functional 3 foot inlet from MLR conventionand brigade millenium. This drains into 4x4x5(ft) silt trap. Quantities unknown.

OverflowsThe excess water taken away by 4 (2ft dia) pipes which is clogged with garbage. These haven't seen usage for almost 3 years now.

Constructed Wetland

• The wetland is about one sixth the size the lake. The inlets are 4 storm water drains and 1 treated water pipe. It sees 4.5 lakh liter of water per day. The wetland is covered with macrophytes alligator weed, cyperus, typha and sees a considerable algal bloom. Water is open only in a few places and mostly stagnant. African tulips, Singapore cherries and pongomias are some of the trees that border the wetland. Also, there is a noticeable amount of suspended physical matter.

Trees observed• Thespisia• Cassia fistula• Vitex nigundo• Arjuna terminalia• Jamun• Soapnut• Vetiver• Ficus Benjamina• Spanish cherry• African tulips

Other Info

There is a planted island in the lake which is about one sixth the size of the lake. he local slums also have small vegetable and fruit patches growing Papaya, Moringa, Guava and Banana plantations. The slum is about 1 acre and 20 guntas which they are likely to convert to an amphitheater post relocation.