Phrae is located in the upper northern region of Thailand, its topography is a depressed area in which situated community areas with Yom River flowing through. The area upstream is mainly mountain range. Due to this topographical feature, several areas are flood-prone, especially at the time of heavy rainfall or excessive flow in Yom River. A disastrous flood occurred in 1995. There were extensive inundation in the municipal areas with flood depth as high as 2 m. in places. The resulting large flood damage ranges from the people livelihood, public and state property damage to the damage of various infrastructures. The Public Works Department (PWD) then initiated the feasibility study of the detailed design for flood protection systems for community areas in Phrae with the main objectives of protecting and mitigating future flood damage. Progress Technology Consultants Co., Ltd. has been contracted to undertake the study which consists of the preparation of a master plan for flood protection systems, a feasibility study for selected areas and the detailed design of the flood protection system.

The Master Plan for flood protection systems for all 13 municipalities in Phrae had identified three prioritized areas which are eligible for the feasibility study. These areas are Phrae Municipality and connected community,  Thunghong Municipality; both of which are the main communities located within the Phrae Town Planning area, and Denchai Municipality.

The subsequent feasibility study has undertaken analyses to select suitable flood protection methods as well as the degree of flood protection or the appropriate return period for the design.

The study has identified components of the flood protection system for each area as follows :

1. Phrae Municipality and Connected Communities

The target is to prevent flood at 75-year return period. The study area is divided in 3 areas, components for each area are as follows:

1. To construct a dike surrounding economic area and raising the level of entrances along the old city wall.
2. To improve Huay Maekame for 2.4 km., constructing a control gate at the barrage in  Huay Maekame and to improve tributaries of Muanghit for a distance of 0.8 km.
3. To construct 7 regulators, 2 pumping stations and improving drainage pipes in main streets of municipal area.

1. To extend the dike in Area 1 to protect Phrae Municipality and parts of Pamat TAO.
2. To improve Lummuanghit in front of Technical College,excavate Lumhuayrongkaw,Rongdaeng and Muangluang and construct 1 regulator.
3. To construct 1 pumping station.

1. To extend the dike from areas 1&2 to protect Thungkwaw TAO and parts of Phrae Municipality.
2. To construct 1 regulator.

2. Denchai Municipality

The target is to prevent flood at 100-year return period. The study area is divided in 2 areas:

Area 1  :  Inner Community

To improve drainage system in the street branches from Tethsaban Soi 9 Rd. to Wat Denchai and Tethsaban Soi 5 Rd., as well as to improve Huay Maepawk

Area 2  : Medium Densed Community and Agricultural Area

1. To construct a polder for community area by constructing 1.0 km. long protection dike along the Yom River and raising 0.8 km long road from Pumping Station to railway.
2. To construct 3 regulators.

3.     Thunghong Municipality

Since the community area of Thunghong Municipality is not affected by water level in the Yom River

1. To improve Klong Rongphong
2. To construct drainage pipes in Tethsaban soi 6, 7 and 10 roads.
   

From the results of economical analysis, it can be concluded that the Feasibility Study for the Detailed Design of Flood Protection Systems for the Community Areas in Phrae has identified 2 areas suitable for the project implementation as follows:

1. Phrae Municipality (area 1)    
2. Denchai Municipality (area 1)