Erbil Governorate, Autonomous Region of Kurdistan, Iraq
Proposed hydraulic works downstream of the designed dam Bastora are located in the valley of the same name, a tributary of the Greater Zab River.
Administrative, the sites of the weirs are located in Erbil governorate, the limit of Shaqlawa districts and Dashti Hawler Erbil.
These works consist of 5 small overflow weirs mainly intended for raising the groundwater level in the area.
The water storage will provide water, for different purposes during the drought season:
– Irrigation possibility for agriculture land
– Water supply by raising the underground level.
In the pre-feasibility study were analyzed two locations for each weir and 3 solution for the execution of the weirs:
1. Weir made out of Rockfill concrete impervious with a concrete mask
2. Weir made out of Rockfill concrete impervious with a geo-membrane mask
3. Concrete gravity type.
The final approved solution of weirs type: concrete gravity.
Considering the Hydrological Study and follow-up of the beneficiary’s investment advice, methods of execution of works, and those in the process of execution, but also the needs of similar experience in Kurdistan, it was considered only discharge free version without the use of the hydro-mechanical equipment.
The spillway dam with free level of overflowing is the optimum choice for maximum safety utilization.
It has to be mentioned that it was considered the unreinforced concrete and reinforced concrete to be used for the construction of the weirs, as the most corresponding and efficient solution, observing the small dimensions of the dams and the geological and geotechnical background.
FEASIBILITY STUDY AND DESIGN FOR GUNJREN DAM
Sulaymania Governorate, Mawat Dist., Kurdistan, Iraq
Gunjren Dam site studied is in North East of Iraq, in Southern part of Kurdistan Region – Sulaymania Governorate. Access to the area is made of road between Sulaymania and Mawat. The site studied is located in the high folded zone, approx. 27 km north and northeast of Sulaymania City and 12 km northwest of Chwarta town. Gunjreen proposed dam is located in Cham-I Daraban valley, a tributary of the Aw-e Qala Chuwalan River, which flows into Lesser Zab river.
The Dam has the following purposes:
– Ensuring the debits necessary for irrigation of 308 ha in downstream;
– Ensuring the water flow necessary for the functioning of a micro power of 70 Kv, located downstream of the dam, on the right shore;
Crest elevation in Gunjren dam, due to the conditions offered by the right slope is to be 881.00 m.a.s.l. The normal water level is to be at 877.00 m.a.s.l. and the maximum water level is to be at 680.70 m.a.s.l. The elevation of the bottom outlet will be at 878.83 m.a.s.l., this will help in flushing extra sedimentation and hence longer life of storage.
• Volume of dead storage level (DSL) = 392,270 m3 at elevation 858.75 m.a.s.l.
• Volume of normal water level (NWL) = 3,521,650 m3 at elevation 877.00 m.a.s.l.
• Volume of maximum water level (MWL) = 4,116,342 m3 at elevation 878.83 m.a.s.l.
• Net life storage = 3,521,650 m3 – 392,270 m3= 3,129,380 m3
• Surcharge storage = 4,116,342 m3 – 3,521,650 m3 = 594,692 m3
The accumulation is composed of:
Rock fill dam with mask of reinforced concrete on the upstream face;
High water discharger.
Concrete faced rock fill dam
Upstream of the dam will be executed plinth sealing veil. The veil is to seal the dam foundation which has a relatively high permeability.
High water discharger
The surface discharger is located on the left shore, being a reinforced concrete construction. The water is released freely.