ulhas river Waldhuni Nalla flood control

Ulhas river originates at an altitude of 821 m. (2694’) near village Thakurwadi. The total length of the river upto Dombivilli from the origin is about 112 Km. The main tributaries of Ulhas river are Murbadi, Barvi, Poshir, Shilar (Chitri), Bhatsa, Kalu and Waldhuni.
There are only two major existing storages namely Bhatsa on Bhatsa river and Barvi on Barvi river in the catchment of Ulhas river. There are two weirs on Ulhas river namely Mohne weir and Jambul weir.
The total catchment area of Ulhas basin is about 4900 sq. km. The break up of this area for Ulhas and its tributaries is as under:
Table : 1 :
Sr.No
River / Basin
Catchment area Km2
1.
Bhatsa river upto confluence with Kalu river
977.81
2.
Kalu river upto confluence with Bhatsa river
1100.00
3.
Ulhas river upto confluence with Bhatsa river
1457.20
4.
Free catchment from confluence upto Dombivilli
113.75
5.
Free catchment below Dombivilli
1251.24

Total
4900.00
River Gauge Data :
River gauging site across Ulhas river near village Badlapur is established by CWC. Yearly maximum peak discharges observed at above gauging site Of the data made available in 1988 maximum discharge of 4440 cumecs was observed.

River Waldhuni and Badlapur nalla are left bank tributaries of Ulhas River. These flow through thickly populated area, which was severely effected during the floods of July 2005. There are numerous constructions in the river channel, which obstructs the waterway
Ulhas river:
There are no major encroachments in Ulhas River. Few low level causeways exist on Ulhas river. The water way of these structures appears less, however, the afflux due to these will not affect urban areas as there is no habitation on the banks of Ulhas river.

Waldhuni river
a) The rivers have been encroached in almost all reaches. In few reaches width of the river has reduced to 10 metre. The water way provided for the bridges and the causeways is very less. These get choked by the solid waste dumped in the river. This is the main reason causing the area to be flooded during heavy rains.
b) The river banks of the Waldhuni River are of lesser heights and the cross section area of the natural river is less as compared to the requirement of area to accommodate the flood within river banks. So the floods of lower magnitude spills outside the river channel and the area gets flooded.
c) There are rock outcrops at certain places and the river slopes are also not uniform. Due to this the hydraulics of channels gets affected during flood.
d) The water way provided for the structure constructed across river Waldhuni especially at the railway crossing is very less as compared to the required waterway. This is also one of the reasons to increase the afflux and the area to be flooded during floods.
e) Several causeways and obstructions have been constructed in the river channel which reduce the effective cross sectional area due to which the flood water level increases resulting in flooding the area on the bank during floods.


Culvert and causeways:
On Waldhuni River and Badlapur nalla, it is seen that low level causeways with hume pipes have been provided. This causes afflux in the upstream
Foot bridge:
Numerous foot bridges have been constructed on Waldhuni, Badlapur nalla and its tributaries. The abutments of such foot bridges are almost in the incise section of the channel, thus reducing the water way
Raw water pipe lines and drainage line
The drainage lines run across the river above river bed at many places, this causes obstruction in the flow
Railway crossing - Railway bridge on Karjat line :
The railway (Karjat line) bridge on Khedgolavli nalla has been provided with an opening of 9 sq. m. This is very less. This spot is the bottle neck for passing the flood
Encroachments due to slum area, plinths, retaining walls, houses have reduced the flow areas considerably
The releases of effluent without treatment is hazardous. There are ample number of such points along the river, where untreated effluent from industries and household is being released
Continuous and vigorous programs for seeking participation of local people and creating awareness among them about purity of water, need to keep the rivers and nalla clean etc. needs to be launched. NGO’s can take up these assignments