Bagmati River Basin Improvement Project – BIP: PIIU-ICB/01- Detailed design of Nagmati Dam (43448-013) LOAN-3057 NEP


Funding Agency: Government of Nepal
Client: Project Implementation (Irrigation Unit)
Date: Nov. 2015 – Sep 2017

The Project is one of the integral components of Bagmati River Basin Improvement Project (BRBIP) and aims to contribute an overall objective of the BRBIP by increasing a volume of water of the Bagmati River in winter season by constructing Nagmati Dam and improving water quality of the Bagmati River.

The main components of the proposed Nagmati dam comprise :

ComponentDescriptionStatisticsAccess road

(Note 2)


From Sundarijal to dam site along the Sundarijal-Mulkarka-Chispani vehicle trackLength Sundarijal to dam site 4 km (all to be upgraded)


DamConcrete-faced rock fillDam height 90 m (Note 1)

Dam fill volume approx. 1.4 Mm3

SpillwayCrest and chute on left abutment,

with flip bucket energy dissipation

device at base

Design discharge capacity 88 m3/s.Outlet worksTwin pipes


? 0.6 m dia cement lined steel pipe with cone dispersion valve

? 1.0 m dia cement lined steel penstock with butterfly valve for hydropower

ReservoirArea at NTWL (1,909.5m): 41.2 ha

Live storage capacity (at NTWL): 7.8 Mm3

Hydropower works


Penstock along left bank of Nagmati / Bagmati River to powerhouse site at Sundarijal? 3,600 m of 0.6 m dia pipe (peak flow 0.8 m3/s)

? 3.2 MW installed capacity (485 m head)

Environmental mitigation


As determined by separate EIA which was produced under the PPTA.

Overall Services provided:

The scope of services will include, but not limited to, carrying out the following activities:

The services are to be taken in two stages, with items (i), (vi) comprising Stage I and items (vii) (ix) comprising Stage II.

i.     Organize and coordinate the execution of the consultancy services

ii.     Engage companies for the supplementary geo-technical site investigation and supervise the execution of the investigations, paying close attention to the management of its timely implementation and quality.

iii.     Undertake topographic surveys of the access road, to serve as the basis to planning upgrading works

iv.     Interpret the findings from the work under items (ii) and (iii) as a key input to the feasibility study updating/upgrading work under (v)

v.     Verify Hydrology and water availability for dry season augmentation in D/S river and possible hydropower generation

vi.     Re-evaluate the engineering proposals in the 2013 feasibility study to upgrade the design in respect to technical and economic feasibility, cost and risk and document the findings in a Revised Feasibility Study report

vii.     Supply the feasibility study for a Government independent peer review

viii.     EIA/EMP – Review the EIA and EMP and update these based on the findings of the updated feasibility study.

ix.     Undertake detailed engineering design of the project works, based on the project layout and design set out in the updated/upgraded Revised Feasibility Study

x.       Prepare tender documents to be applied in recruiting the services of a Consultant to  undertake construction of the project works.