Hiring a consultancy firm for design Review of Warufu 20 m high earth fill dam and 3,000ha irrigation system

Project: Commercialization and De-Risking for Agricultural Transformation Project

REQUEST FOR EXPRESSIONS OF INTEREST

(CONSULTING SERVICES -– FIRMS SELECTION)

COUNTRY: Rwanda

NAME OF PROJECT: Commercialization and De-risking for Agricultural

Transformation (CDAT) Project

Credit A No: 7084-RW, Credit B No: 7085-RW and Grant No: E017-RW

Assignment Title: Hiring a consultancy firm for design Review of Warufu 20 m high earth fill dam and 3,000ha irrigation system.

Reference No: RW-RAB-527660-CS-QCBS

The Government of Rwanda has received financing from the International Development Association (IDA) toward the cost of the Commercialization and De-risking for Agricultural Transformation (CDAT) Project and intends to apply part of the proceeds for consulting services for hiring a consultancy firm for design Review of Warufu 20 m high earth fill dam and 3,000ha irrigation system.

The Terms of Reference (TOR) related to this assignment are attached to this request for expressions of interest.

The Rwanda Agriculture and Animal Resources Development Board (RAB) / Commercialization and De-risking for Agricultural Transformation (CDAT) Project now invites eligible consulting firms (“Consultants”) to indicate their interest in providing the above Services. Interested Consultants should provide information demonstrating that they have the required qualifications and relevant experience to perform the Services. Expression of Interest (EOI) will include: core business and years in business, relevant experience, technical and managerial capability of the firm.

To be able to submit an expression of interest, International and National consulting firms who are not registered in E-procurement system, are advised to register themselves through www.umucyo.gov.rw

N.B.:

Submission of expression of interest via other channels than Umucyo E-Procurement System shall not be considered.

The shortlisting criteria are:

• General experience of at least 15 years in the design of large dams and pressurized irrigation schemes;
• Specific experience proven by certificates of good completion and contracts in design of large dam (Embankment) and appurtenant structures, diversion weirs and pressurized irrigation mainly center pivots.

The shortlist will contain five (5) to eight (8) firms.

The attention of interested Consultants is drawn to Section III, paragraphs, 3.14, 3.16, and 3.17 of the World Bank’s “Procurement Regulations for IPF Borrowers” Fourth Edition September, 2023 (“Procurement Regulations”), setting forth the World Bank’s policy on conflict of interest.

Consultants may associate with other firms to enhance their qualifications, but should indicate clearly whether the association is in the form of a joint venture and/or a sub-consultancy. In the case of a joint venture, all the partners in the joint venture shall be jointly and severally liable for the entire contract, if selected.

A Consultant will be selected in accordance with the criteria set out in the Request for Proposals.

Expressions of interest must be delivered through e-procurement system on www.umucyo.gov.rw by the time indicated in the system.

TERMS OF REFERENCES FOR

DESIGN REVALIDATION AND UPDATE OF WARUFU DAM AND IRRIGATION NETWORK (3,000 HA COMMAND AREA)

LOCATED IN GATSIBO AND NYAGATARE DISTRICTS

1. Project Background

The World Bank approved $300 million in financing under the International Development Association’s (IDA’s) grant, credit, and scale up window to help the Government of Rwanda increase irrigation, commercialization, and access to finance and insurance for farmers and other value chain actors in Rwanda’s agricultural sector.

The Commercialization and De-Risking for Agricultural Transformation Project (CDAT) will support the Government to provide services and create an enabling environment for the private actor throughout the agricultural value chain. It will finance public investments in the seeds sector, develop and rehabilitate irrigation systems on over 17,600 ha, provide accompanying land husbandry development on about 11,000 ha in surrounding water catchment areas to increase productivity and promote climate smart agriculture.

The project will also support commercialization by helping farmers access to markets and availing matching grants for investments in mechanization, post-harvest infrastructure and processing equipment. An innovation challenge fund will invest in particularly innovative solutions for the sector that can be brought to scale. The project is nationwide and is foreseen to directly benefit at least 235,000 households, including women and youth.

In partnership with financial institutions, the Commercialization and De-Risking for Agricultural Transformation Project will seek to enhance access to affordable financial services and products in the agricultural sector. This can be achieved by providing long-term financing, reducing risks and challenges faced by agricultural value chains through strengthening market linkages and scaling up agriculture insurance.

In this regard, part of the project’s funds will finance the consultancy services to revalidate and update the design of Warufu dam and irrigation network (3,000 ha gross command area) located in Nyagihanga, Gatsibo, and Ngarama Sectors of Gatsibo District, and Mimuli Sector of Nyagatare District.

1. 1. Site Description

Warufu site is located on the border of Gatsibo and Nyagatare Districts which is a semi-arid zone with average annual rainfall of 900mm, and temperatures ranging from 210C to 280C. The Warufu site is a multi-purpose project aiming at developing 3,000 ha irrigation system, providing drinking water supply of 5,000m3/day to 240,000 people and generating 1,260 MWh/yr electricity sufficient to light about 4,000 houses in the project area. It involves a 20 m high dam (above river bed level) to store 25 Million m3, 3,000 ha irrigation system, and land-husbandry technologies in the irrigation area and catchments. Water supply outlets for hydropower and domestic water supply will also be provided. The detailed study was developed and approved by the former LWH, World Bank funded Project under MINAGRI in 2017.

Figure 1- : Warufu Large Dam and Hillside Irrigation command area (3,000ha)

This consultancy service is related to the design revalidation and updating of Warufu Dam on the Warufu River, and the command area. The proposed dam site is located 0.7 km upstream of the road bridge next to Nyagahanga town. The dam is reached from either the Kayonza – Kagitumba asphalt road and then the earthen road near Kabarore Gatsibo, or the Kigali – Byumba asphalt road and then the Byumba – Nyagatare asphalt road to Nyagahanga town where the dam site is located. The coordinates of the dam axis are E 524,795/ N 4,821,009.

1. 1. Brief Description of the Dam components

Warufu Dam has the following components:

• Warufu dam is a homogenous embankment dam incorporating a cofferdam, with a concrete frontal spillway, chute and stilling basin and a diversion/intake/outlet works system designed to release water for irrigation, hydropower, environmental compensation flow and domestic water supply, as well as to ensure bottom outlet operations.
• Associated rehabilitation of existing roads affected by the new reservoir and ancillary works.
• The dam crest is at +1,546.60 m elevation, with the full supply level (FSL) of the reservoir at +1,543.50 m. The minimum supply level (MSL) that has been determined for irrigation is +1,533.40 m, ensuring a live storage volume of 22.6 MCM. The intake structure provides the possibility of abstraction to a lower level at +1,533.00 m to allow for additional abstraction as sediment accumulates in the reservoir. The maximum flood level (MFL) for the routed flood of 10,000 years return period (81m3/sec) is 1,545.93 m. The dam crest width is 7.0m and the dam embankment slopes are 3:1 (H:V) at both the upstream and downstream faces, and the same is valid for the cofferdam. The dam height is 26.1 m from the lower elevation of the cutoff, whereas 20m from the river bed level. The entire cofferdam will be incorporated in the upstream section of the embankment during the construction of the dam.
• The diversion works consist of a cofferdam and a steel diversion pipe. The total length of the diversion works is 146 m, with inlet invert elevation at +1,525.60 m and outlet invert elevation at +1,525.15 m, corresponding to a longitudinal slope of S=0.003. The proposed diameter of the diversion pipe is selected based on the routed design flow of 11.8 m3/sec, for T=5 years return period, and the elevation of the cofferdam crest is set at +1,533.50 m. The nominal diameter of the pipe is D=1.6 m and steel lining thickness of 8.2 mm.
• Warufu dam has a frontal concrete spillway on the left abutment. The spillway design flow is 81m3/sec, corresponding to 10,000 years return period, with the exception of the stilling basin, the design flow of other spillway components is only 35m3/sec, corresponding to 100 years return period which shall validated. Designing all spillway components with 10,000 year flood shall be considered during the design review. The spillway works consist of three components, namely: The spillway control section, the chute and the stilling basin.

The outlet pipe will serve for diversion during construction but later it will be used for both water supply and bottom outlet after the completion of the works. A vertical concrete intake shaft square in plan with openings equipped with trashracks on all four sides and a short steel pipe section of 1.6m nominal diameter will be constructed to convey water to the diversion pipe. Grooves have been provided at the openings, where stop logs can be placed in the future in order to isolate the reservoir from the outlet system. At the downstream end of the outlet pipe a concrete structure (valve chamber) will be constructed to house the equipment required for the flow control accompanied by an impact type stilling basin for energy dissipation of the released flows.

The works in the valve chamber include:

• The short extension of the outlet pipe and the installation of a taper section for the gradual transition from 1.6 m to 1.1 m diameter and a short pipe section of 1.1 m diameter, where two butterfly valves of 1,100mm diameter will be placed to regulate the bottom outlet operations, whenever required. An access manhole is provided on the 1.6 m diameter section which will be used whenever internal inspection of the outlet works is necessary.
• The construction of 800mm diameter branch of the main pipe for irrigation, hydropower and compensation flow releases. This will be equipped with a butterfly valve and a flow regulation needle valve, both 800mm diameter. The branch is then separated into two pipes of equal diameter, one leading to the nearby future power station and the other directly to the downstream riverbed. A 250mm branch of the main pipe will also be provided for the domestic water supply connection and will be equipped with valves.

1. 1. Brief Description of the Irrigation component

The Warufu project command area is located mostly in Gatsibo District with a downstream section extending into Nyagatare Districts. The irrigation scheme is divided into upper and lower pressure zones with a total of 3,000ha gross (2,545ha net) and the Conveyance System that conveys the water to the head of the irrigation network.

Water released from the dam flows down the stream to a stream diversion structure which diverts water into a 7km long concrete lined canal leading to the command area., A smaller upper regulating reservoir will support irrigation of the upper irrigation zone, and a larger lower night storage reservoir will support irrigation of the lower irrigation zone., During the day water from the canal water will be used to irrigate the upper zone, and fill the lower reservoir whereas during the night generating hydropower. Gravity irrigation will be employed by pipe networks for each zone from their respective reservoirs.

1. 1. Salient features of the Irrigation component:

Conveyance System
Stream Diversion Structure	Concrete Weir, 4m high
Conveyance Canal	7.1 km
Nr of Pipe Culverts	9
Nr of Box Culverts	8
Irrigation System
Net Command Area – Upper Zone	1,072 ha
Net Command Area – Lower Zone	1,473 ha
Main Pipes	94.4 km
Secondary Pipes	361.1 km
Pipes (D40 – D315)	417 km
Pipes (D355 – D1000)	38.5 km
Nr of Major Culverts Rectangular	52
Nr of Minor Culverts	84
Hose Pipes	3250 hose pipes, 9000 outlets
2 Reservoirs	42,000 m3 Total Capacity

1. Validating and updating the Design Study
   1. General

The detail design was completed in 2017; therefore, there remains scope to review, update, and enhance certain elements of the scheme.

Potential positive impacts from updating the design are:

• Improve functionality by incorporating the experience of the Client and Designer gained from other projects;
• Improve the design to state-of-the-art design practices and also dam safety requirements in line with the ICOLD guidelines
• Introduce new technologies to reduce labor and increase water use efficiency;
• Check capacity of the system for resilience to climate change conditions;
• Incorporate infrastructures (roads etc…) that have been constructed after completion of the design;
• Reduce the cost of the project.

It should be noted that the assignment is done basically based on existing data and additional investigations are limited. However, reviewing and updating the hydrological studies and other social and environmental baseline data to the current year is necessary.

1. 1. Scope of Work

The consultant will perform the following tasks during the design revalidation and update phase:

1. Consultant will conduct a comprehensive review of existing design identifying potential areas for improvement by identifying gaps in the design of the dam and appurtenant structures
2. Update the hydrological studies to the current year by acquiring recent flow records and climatological data.
3. Review and update the reservoir simulation (water balance) considering the possible changes in the demand and water supply delivery horizon with the consultation of different stakeholders like WASAC and downstream irrigators.
4. No major design validation and revision will be made on the hydropower component of the project. If deemed necessary, it should be subject to conditional and prior Client approval. The bill of quantity should be reviewed to match the current market condition.
5. Review and update the standard design flood and safety check flood by considering the ICOLD and other relevant guidelines. Presence of a small town (Nyagahanga) downstream of the dam should be considered during revalidation and updating the safety check flood.
6. Review and optimize the selection of the diversion flood, fixing the coffer dam level and the size of the diversion conduit.
7. Review and update the sediment yield estimation and fixation of the dead storage level. Where appropriate the consultant may undertake sampling during the design review
8. Carryout sediment distribution modeling in the reservoir with the appropriate method of either area reduction or area increment approach.
9. Establish a new gauging station that will be used for continuous recording during construction and to be used for future operation.
10. Validate and revise the design of the spillway based on the updated design flood and also the discharges to be used for the spillway chute and stilling basin design.
11. Review the geotechnical investigation like drilling and construction material assessment done in the previous study for its adequacy and also propose additional investigation for implementation during construction stage (direct investigation drilling and indirect investigation geophysical survey) by critically reviewing the drilled bore holes, collected samples and laboratory tests. No actual drilling and geophysical survey investigation will be done during this design review phase only recommendation will be made to be carried out during the early phases of the construction stage.
12. Validate the construction material investigation. Where appropriate the consultant may propose additional investigation during construction.
13. Validate the engineering properties of the dam fill materials
14. Review and update the dam crest level determination taking into account the safety check flood, free board estimations procedures and some depth for road surfacing purposes.
15. Review and update the general as well as cutoff foundation excavation levels to account for the foundation material variability and dam height across the valley. The general and cutoff foundation excavation depths shall not be considered uniform across the dam axis.
16. Revise and update the slope stability analysis by undertaking sensitivity analysis of the design parameters (the design parameters like the shear strength, unit weight and hydraulic conductivity). The estimated factor of safety in the detailed design seemed marginally safe and some of the design parameters seemed conservative.
17. Carryout stress and deformation analysis of the dam with standard geotechnical software to complete the manual computations done in the detailed design.
18. Review and confirm the materials proposed for embankment fill material are not susceptible to piping and also liquefaction under small earthquake shaking.
19. Check and confirm the foundation soil for any potential liquefaction related problems though the project area is located in less active seismic zone part of Rwanda.
20. Review and update the filter gradation design with due consideration of the base material boundary curves. The lower and upper boundary of the homogenous fill materials should be plotted based on the test results of each samples collected during detailed design. All necessary corrections for particle sizes greater than 4.75mm should be made as this is important for filter design.
21. Review and update the seepage treatment measures design. Carryout detailed analysis by varying the length of the upstream clay blanket and thickness till acceptable seepage quantity is achieved and at the same time it doesn’t pose any risk to piping of the foundation soil.
22. Review and update the reservoir rim stability and propose engineering solution to minimize slope failure inducing sediment movement towards the reservoir.
23. Review and update dam instrumentation to include additional instruments for measuring settlement and also open standpipe for pore pressure downstream of the dam. Also include surface monument (bench marks) for measuring the horizontal and vertical movement of the dam
24. Review and update the structural design of the intake tower, diversion conduit and spillway control section, chute slab, stilling basin and side walls. The structural design calculations and models shall be submitted with the final design report.
25. Consultant will conduct a comprehensive review and validation of existing design identifying potential areas for improvement, and evaluating the feasibility of implementing advanced irrigation technologies (precision irrigation technologies).
26. The irrigation pipe network will be redesigned to support the new and approved irrigation systems with center pivot, portable sprinkler, and hydrant-hose irrigation systems, in order of priority. Accordingly, the review and validation shall include redesign of the irrigation pipe network, optimization for center pivots/sprinklers, hydraulic reconfiguration, and related irrigation modernization activities.
27. The consultant will assess current climate conditions and potential future climate scenarios to ensure the system is resilient to climate variability and change.
28. Introduce where possible, advanced technologies like center pivots and sprinklers and prepare subsequent designs and bill of quantities.
29. Prepare an updated bill of quantities for dam, outlet works, diversion weir and irrigation components with new prices.
30. Prepare updated technical specifications and tender documents based on appropriate World Bank guidelines.
31. Prepare three separate Works lots (dam and diversion headwork works as one lot and two lots for irrigation) which shall be further discussed with the consultant.
32. Prepare updated operation and maintenance manuals for dam and irrigation.
33. Prepare an updated dam break analysis report.
34. Prepare an updated emergency and preparedness plan for the dam
35. Assess the physical features and quantify that could hamper the construction for main project infrastructures: (Dam, Irrigation, Diversion Head Works, Canal Works and reservoirs)
36. Make presentations to the Dam Review Panel of Experts and address their comments

1. 1. Profiles of Consultant’s Staff

The Consultant will provide at least the following personnel:

1. Civil engineer or irrigation engineer or hydraulic engineer as Team Leader (with MSc level in their discipline) with at least 15-years general experience, having at least seven (7) references of specific experiences as head of mission on studies for the planning, design and implementation of pressurized irrigation projects and dam and appurtenant structures in developing countries. Good organizational and coordination skills and excellent working knowledge of English
2. Hydrologist: The Hydrologist will have a minimum of a MSc degree in Civil /Water Resources Engineering (hydrology major) and 15 years of demonstrated/proven working experience, including a minimum of five (5) references of specific experience in hydrologic studies related to storage reservoirs, dam break analysis and preparation of emergency preparedness plan.
3. Dam/Hydraulic engineer: The Dam/hydraulic engineer must have a minimum of a Master’s Degree in Civil/Hydraulic Engineering with 15 years of demonstrated/proven professional experience in dam design and construction works, with working knowledge of English, having at least seven (7) references of specific experiences as Dam Expert for design studies.
4. Irrigation engineer (with MSc in Civil Engineering or Irrigation and Drainage or Agriculture Engineering, with proven general experience of at least 10 years with working knowledge of English, having at least five (5) references of specific experiences as an irrigation engineer on studies for the planning, design, and implementation of pressurized irrigation projects and with expertise in design advanced irrigation technologies, such as center pivots and sprinklers including hydraulic modeling of irrigation pipe networks.
5. Economist with a minimum of MSc level in Economy or Socio Economy with the proven general experience of at least 10 years with working knowledge of English, five (5) specific studies on irrigation projects, preferably in Rwanda;
6. Environmental and Social Specialist: With at least MSc, qualification in environmental studies, and at least 5 years of general experience with three (3) references of specific experience proven with service certificate in Environmental Assessments. Knowledge of World Bank Social and environmental safeguards is a must.

The consultant will bear all mobilization, logistics, equipment costs, consumables, and related costs necessary for the proper and timely execution of the services requested for this study.

Man, months allocations.

Staffs	Man Months
A civil engineer or irrigation engineer or hydraulic engineer (Team leader)	6
Hydrologist*	5
Dam/Hydraulic engineer	5
Irrigation engineer	5
Economist	2
Environmental and Social Specialist	2

Note: (*) the hydrologist will be also responsible for preparation of dam break analysis and emergency preparedness plan.

1. 1. Time Schedule per Expected Deliverable

The assignment is expected to take a maximum of Six (6) months. The set period was proposed considering the timeline for each deliverable including the validation sessions being subject to comments and time to address them. Therefore, the documents and reports should be submitted as follows:

S.No	Deliverable	Timeline	Time line from contract signing
1	First report and its presentation to the Client	One month	End of Month 1
3	Draft Updated detailed design report and its presentation to the Client	Three months	End of Month 4
4	Final Updated Detailed Design	Two months	End of Month 6

1. Requirement for Reports and Documentation

All the reports, documentations, calculations and drawings produced by the Consultant as part of the services under this agreement are the sole property of the Client and the Consultant shall not reproduce it or give to any third party without the consent and written approval of the Client.

In performing his duties under this agreement, the Consultant shall submit to the Client the following reports (and others as may be required during the course of the Project). The total number of copies of each report and document to be prepared by the Consultant during the services period is listed below:

Reports	Submission Schedule	Copies
First report	End of first month	2 Sets
Draft Updated detailed design report and its presentation to the Client	End of Fourth month	3 Sets
Final Updated Detailed Design	End of Sixth month	5 Sets

The deliverables of this study should be aligned as validating the original design, updating the existing design by critically stating the reason for changes. The following design component will shade light to the cause and effect to be followed in the design review assignment process.

• • Hydrology: updated due to revised climate/hydrological data
  • Spillway: Updated after flow review
  • Irrigation layout: redesigned for center pivot optimization
  • Hydropower: remained with minor adjustments
  • Dam Safety Reports: a need to revise dam break analysis and updating emergency preparedness plan

• First Design Report: The report will provide details of the design gaps identified, the methodologies to be adopted, revised work schedule, and confirm the approaches to be followed throughout the entire design validation and updating for the dam and irrigation system.

• Draft Updated Detailed Design Report: The Consultant shall submit a draft updated detailed design report that encompasses all components of the design validation and review study of the dam and appurtenant structures, validated and hydrological study report, updated bill of quantities, drawings, technical specifications, dam break analysis report, and dam and irrigation Operation and maintenance manuals.

• Final Study Report: The final report of the dam and appurtenant structures will be submitted together with the following revised documents: tender documents (i.e., bill of quantities, technical specifications, and drawings), revised EFA (economic and financial analysis), EPP (Emergency Preparedness Plan) with dam break analysis annexed to this report), final dam and irrigation Operation and maintenance manuals, construction supervision and quality assurance manual

1. RESPONSIBILITY OF THE CLIENT

The client will:

1. Ensure free access to all sites and locations connected with the execution of the study;
2. Provide the Consultant with any assistance as the Consultant may be entitled to in accordance with the Terms of Reference;
3. Provide the Consultant with all documents, information reports, data, any existing photographs and other information pertaining to the study that are available and not withhold any information pertinent to the Consultants work.
4. Facilitate the issuance of work permits and entry visas for the Consultant’s expatriate staff.
5. Facilitate the import and export of any required equipment and supplies Following formal request from the consultant which believed to be related to this assignment only.

1. RESPONSIBILITY OF THE CONSULTANT

• The Consultant shall carry out the study in a professional manner in keeping with internationally accepted standards; using qualified and appropriate staff. They shall endeavor to implement the assignment with diligence and within the time agreed upon in the contract. In this regard the Consultant shall furnish to the project the full curriculum vitae of each of the members of the team it proposes for the study.
• The Consultants shall be responsible for providing his staff all payments including salaries, flight, and travel including visas. The Consultants shall replace any staff member who is unable to carry out the work or is considered by the Client to be unsuitable. As per the rules in keeping with internationally accepted standards for assignment of this nature, the replacement of any of the Consultants' staff should be by a person of equal competence at the same cost and subject to the approval of the Client.
• The Consultant shall be responsible for its office costs, the cost of housing and other services for his staff whilst in Rwanda, office renting and facilities, technical equipment (where applicable), and hire of vehicles needed for the study.
• The Consultant shall be responsible for arranging and meeting the cost required to accomplish the study in accordance of the Terms of Reference.

1. Consulting firm profile

The consulting firm should have at least the following profile:

• General experience of at least 15 years in the design of large dams and pressurized irrigation schemes;
• Specific experience proven by certificates of good completion in design of large dam (Embankment) and appurtenant structures, diversion weirs and pressurized irrigation mainly center pivots.
• Knowledge of international standards and best practices for irrigation scheme design and construction.
• The consulting firm should have experience in working in the region.

1. Payment schedule and Modalities

The consultant shall be paid by per deliverable as follows:

Payment Number	Event	Payment or Installment (%)
	First report	20
	Draft updated design report	40
	Final detailed design report	40