The Subarnarekha is one of the longest east flowing inter-state rivers. It originates near Nagri village in Ranchi district of Jharkhand at an elevation of 600 m. The total length of the river is about 395 km. The principal tributaries of the river are Kanchi, Kharkai and Karkari.The basin lies between North latitudes of 21° 33’ to 23° 32’ and East longitudes of 85° 09’ to 87° 27’ situated in the North-East corner of the peninsular India. It is bounded on the North-West by the Chhotnagpur Plateau, in the South-West by Brahmani basin, in the South by Burhabalang basin and in the South-East by the Bay of Bengal.
The total catchment area of the basin is 18,951 sq.km. The state-wise distribution of the drainage area is shown as below.
|Sl.No.||Name of State||Catchment Area(sq. km)||Percentage of total|
The catchment areas of the important tributaries are given below.
|Sl.No.||Name of the River/ Tributary||Bank||Length(km)||Catchment area(sq. km)||% w.r.t total|
The basin is generally influenced by the South-West monsoon, which onsets in the month of June and extends upto October. The average annual rainfall for the basin is around 1800 mm. The climate in the sub-basin is tropical with hot summer and mild winters. The mean monthly temperature varies from 40.5° C (May) to 9.00 ° C (December). The highest temperature recorded is 47.2° C and the lowest is 2.8° C. Annual average maximum and minimum temperatures vary from 32.4° C to 18.0°C.
The geological formations occurring in the basin are (i) Pre-Cambrian or Achaean (ii) Tertiary and (iii) Alluvium plains. Out of these, Pre-Cambrian formations mostly cover Jharkhand and West Bengal regions and Tertiary and Alluvium plains cover the basin area in Orissa. The Achaean formations mostly comprise Geneiss, Micagenists, Phyllites, Dolomites and Granites. The underlying rock is highly undulating.This region contains some of the richest coal and ore deposits like iron and bauxite.
Water Storage/Diversion structures
|Sl.No||Name of Project||River||Status|
|1.||Torlow||(Tributary of Kharkai)||Existing|
STREAM FLOW DATA
Area-velocity method is generally adopted for measuring discharge at 5 sites. Cup type current meter is used to measure the velocity of flow and the depth is measured by using sounding rod for depths up to 3m and by log line beyond. Discharge by area velocity method is observed once in a day starting at 0800 hrs at all the sites except on Sundays and holidays. Besides, silt and water quality observation are also being made at Sites: Jamshedpur, Adityapur, Ghatshila and Water quality observations at Site: Muri
Computation of daily flows
The observed stage and discharge figures for each season (monsoon and non-monsoon) are plotted and a mean Stage Vs Discharge curve is drawn, giving due attention to the scattered points with reference to area velocity etc. The factors responsible for the shifting of the curves are also taken care of by studying the river cross section at regular intervals and with super imposition of previous year Stage Vs Discharge curves. Accordingly, the trend of the current curve is finalised. Finally, the discharges of the non observed days are computed from these Stage Vs Discharge Curves. Similarly, for non-monsoon period also, the daily discharge for non observed days is computed.
|Sl. No.||Code No.||Station Name||Type||Data available|
|1.||ES000R3||Muri||GDQGauge Discharge Water Quality||GGuage-20.08.88--Continuing|
|2.||ES000N5||Jamshedpur||GDSQGauge Discharge Sediment Water Quality||G-24.06.71 -- Continuing|
|4.||ES000K7||Ghatsila||GDSQ||G-16.03.71 -- Continuing|
|5.||ESA00F3||Fekoghat||F.F &GDGauge Discharge||G-01.07.87 -- Continuing|
|D-18.06.88 -do- (Seasonal)|
|6.||-||Jamsholaghat||GD||G -21.06.1973 -- Continuing|
|D -17.6.2004 -do- (Seasonal)|
|7||-||Ghatsila Rd Bridge *||Q||Q-01.04.91 -- Continuing|
|8.||-||Baridhi Nala *||Q||Q-01.04.91 -- Continuing|
|9.||-||Kulpatanga *||Q||Q-01.04.91 -- Continuing|
Note: * These are Water Quality sample collection points. No regular CWC set up exists.
Water Resources Projects
|Major Medium Irrigation Project||Dams|