Project Name: Feasibility and Environmental Impact Study on Kok-Ing-Nan Development Project

Firm Name: TEAM Consulting Engineering and Management Co., Ltd.

Associate Firms: Panya Consultants Co., Ltd.

ASDECON Corporation Co.,  Ltd.

Sanyu Consultants (Thailand) Ltd.

Location: Chiang Rai, Phayao, and Nan Provinces, Thailand

Project Owner: Royal Irrigation Department

Project Period: 1996-2002

Type of Project: Water Resources Development

Project Description:

It is widely recognized that the regulated water supply in the Chao Phraya river basin in central Thailand is already fully committed. Consequently, the Royal Irrigation Department (RID) has implemented the Kok-Ing-Nan Development Project, as one of the possible options, to divert the surplus water during the wet season from the Kok and Ing basins, the tributaries of the Mekong River, in northern Thailand into the head of the Nan catchment, which forms part of the Chao Phraya river system.

In the wet season, when the river flows far exceed the needs of the catchment, diversion dams would regulate and allow a steady flow along the proposed diversion canals and tunnels to headwaters of the Nan River. With diverted water, additional power would be generated at Sirikit Dam, Nan province, together with additional dry season irrigation in the lower Chao Phraya basin.

The Consultants provides the services in formulation of an integrated operation and management plan of the overall development scheme - the local water uses including irrigation and hydropower requirements, and the trans--basin diversion. Special attention was given to O&M and organization of the Kok-Ing-Nan diversion scheme and development projects, operating methods of water diversion and tele-metering system, maintenance works, manpower requirement, and O&M cost estimate.

Scope of feasibility studies in each basin are as following:

Kok and Ing Basins:

• Primary study areas as water sources.
• Study the present and future trend of water uses and management including potential development and management of water resources with the project.
• Possible alternatives of local development and trans-basin diversion scheme.
• Technical features of diversion routes and structures.

Nan Basin:

• Primary study area as the passage of trans-basin diversion.
• General hydrologic study.
• Potential development and management in water utilization with the Project.
• Required operation and management of Sirikit reservoir, and all irrigation projects in the lower basin.

Chao Phraya Basin:

• Secondary study area as the project beneficiary;
• General hydrologic study;
• Study of present and future trends of water uses and management including potential development and management with the project.

As for the environmental impact assessment studies, works undertaken by the Consultants

are as following:

• Environmental impact assessment, and monitoring and mitigation measures study.
• Environmental impact mitigation and quality enhancement measures covering local employment, watershed conservation and re-afforestation, flood protection using remote sensing system.
• Public relations and social participation as well as organizing public hearing.

Finally, the Consultants have formulated the comprehensive development plan aiming at the optimal long term management and allocation of the water resources of the Kok and Ing basins with minimum negative envi-ronmental effects. The plan reflects maximum potential of water uses and requirements in the local areas of the Kok and Ing basins.

However, the study covers the areas both directly and indirectly related to the development scheme, i.e. Kok, Ing, Nan and Chao Phraya basins. This includes (i) development plans and measures in Kok, Ing and Nan basins; (ii) Kok-Ing-Nan diversion scheme; (iii) operation and management plan; and (iv) long-term basin management plan.