Flood Engineering and Management Division, Department of Engineering Services, Ministry of Works and Human Settlements, Royal Government of Thimphu, Bhutan
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Flood Engineering and Management Division, Department of Engineering Services, Ministry of Works and Human Settlements, Royal Government of Thimphu, Bhutan Preparation of Flood Management Plan for Paro Dzongkhag Draft Terms of Reference (2019-2020) Contents 1. Background ......................................................................................................................................... 2 2.Study Area: ........................................................................................................................................... 3 Pa Chu ................................................................................................................................................. 4 Do Chu ................................................................................................................................................ 4 Streams: .............................................................................................................................................. 4 3. Description of the assignment ............................................................................................................. 5 3.1 General .......................................................................................................................................... 5 4. Baseline information............................................................................................................................ 6 6. Out puts for the studies ...................................................................................................................... 7 5. Requirements ...................................................................................................................................... 7 7. Experts Requirement ........................................................................................................................... 7 7.1. Experience of the consultancy firm and experts ............................................................................ 7 8. Timelines and Deliverable .................................................................................................................. 10 9. Reporting .......................................................................................................................................... 11 Figure 1. Study Area under Paro Dzongkhag ............................................................................................ 3 Table 1. Requirements to produce in the form of map/drawing ............................................................... 7 Table 2. Expert requirement from the consultancy firm ........................................................................... 9 Table 3.Timelines and deliverable report from the consultancy firm ...................................................... 10 1 1. BACKGROUND Bhutan is among the countries most vulnerable to climate change in the Asia-Pacific region because of its vulnerable mountainous terrain and volatile ecosystems. The country is exposed to multiple hazards, in particular glacial lake outburst floods (GLOF) resulting from glacial melting, flash floods, landslides, windstorms, forest fires, localized changes in rainfall patterns and increasing droughts during dry season. Climate change is projected to significantly magnify the intensity and frequency of such natural hazards, as has already been evidenced by the glacial lake outburst flood (GLOF) of Lugge Tsho in 1994, the high intensity cyclone Aila in May 2009, which caused substantial damages and more recently in July 2016, whereby the rivers and streams in southern Bhutan washed away houses, farmland and affected numerous public infrastructure. Flash floods are the most common climate induced hazard in Bhutan. The monsoon season with incessant rainfall through out Bhutan increases the river volumes which run down the steep terrain with high velocity and creates flooding downstream. People have lost lives, properties, agricultural products during such disaster leaving them to start their living from scratch. Vehicles get stranded and school students are unable to attend their classes as the roads and bridges gets washed away.Streams in the country has also led to flash floods and caused enormous impacts to the livelihood. Therefore Flood Engineering and Management Division in its endevour to combat the flooding hazard in all the dzongkhags would like to start the comprehensive flood management program from Paro. Paro valley extends from the confluence of the Pa chu and the Wang chu rivers at Chuzomupto Mt. Jomolhari at the Tibetan border to the North. It is located at an altitude of 2,250m above the sea level. It covers a total area of 1293 Sq. km and has a population of 35,260. The temperature ranges from 26 to 14 degree Celsius in summer and 14 to minus 5 during winter. It comprises of 10 Gewogs, namely, Dogar Gewog, Dopshari Gewog, Doteng Gewog, Hungrel Gewog, Lungnyi Gewog, Naja Gewog, Shaba Gewog, Tsento Gewog, Lamgong Gewog and Wangchang Gewog. The land cover area for forest is 60.9% and for Agriculture is 5.1 %. Like in most part of the country, rivers and streams in Paro dzongkhag also flows through the settlement, infrastructure and agricultural area. There is history of flooding in the main Paro town, Nyemiazampa area and the villages in the gewogs. Although smaller streams flow through the villages, the discharge increases hugely during the peak monsoon time affecting the people and their properties. Hence, there is the need to conduct proper studies of the rivers and the streams in the Dzongkhag, with particular emphasis on their flooding nature in order to place the appropriate measures. 2 2.STUDY AREA: Figure 1. Study Area under Paro Dzongkhag 3 Pa Chu Pa chu is the main river flowing through the Paro town. There are many important public infrastructures, agricultural land, tertiary institutes, national airport and settlements along the Pa chu. During the monsoon seasons, the river discharge increases and poses flooding threat to the settlement and infrastructure. There was history of Pa chu flooding in the year 2009 recently and deadly one in 1968 where the part of Paro main town has been inundated and severe impacts were caused. Although massive flood protection works have been carried out along the river, the risk of flooding cannot be ruled out. Do Chu Itis tributaries of Pa chu and flows via villages under the Dopshashari, Doteng and Hungrel gewog in Paro.There are many important public infrastructures; agricultural landalong the river.As per the hazard report it was found that the BPCColony and agriculture land are found flood hazard zone. Moreover, this river poses threat to Hungrel gewog administration office area. Streams: i) Satshamchu (North side): This stream flows from upper satsham village and run down through the middle of agriculture land and finally joins the Pa chu. Both south and north satshamchu falls under the Tshento gewog. ii) Satshamchu (South side): This is the Satshamchu north side stream which gets bifurcated just above the Zhiwaling resort. It then runs down through Udumvara resort and finally joins Pachu. iii) Dakhorongchu: This stream runs down via Lamgong MS School, Lamgong town area and then joins Pachu. Agricultural lands have been mostly affected due to the Dakhorongchu flooding. iv) Ngobarongchu: It flows though the Meta resort, Tenzin HS School and few of the settlements and then joins Pachu. Agricultural lands have been mostly affected due to the flooding. The present area below the Kichu Lhakhangs was mostly inundated during the flooding. v) Jewchu: Under Lungnyi Gewog, Jew chu flows through the villages, agricultural land, town and the Gewog administration office before joining Pa chu. Jewchu and Gatanarong chu both falls under the Lungnyi Gewog. vi) Gatanarongchu: Is flows though the villages behind the Bondey Town along the present AMC office. Hence, its impact has also been mostly on the agricultural lands in the past. In 1994, the stream flooding washed away a police man. It is also a tributary to Pa chu. 4 vii) Nephuchu: It flows through the Nephu village adjacent to Shaba Higher Secondary School, some residential area and joins to Pachu. The stream falls under the shaba gewog. viii) Richu:This stream flows from Rinchending village and down towards the Dopshari village and adjacent to gewog administration office. Before joining dochu the stream also flows through agriculture land and some settlements of shari village. The stream falls under the Dopshari gewog. 3. DESCRIPTION OF THE ASSIGNMENT 3.1 General The overall objective of the assignment is to prepare a Flood Management Plan (FMP)for Paro Dzongkhag. The management plan should mainly focus on managing flood along Pa chu, Do chu and the eight critical streams as mentioned above in the study area. The FMP should include various plans, programs and measures to make the community, public infrastructures, agricultural land, etc safe and resilient during the time of flooding hazard. The detail task to be performed for the study shall include, but not limited to the following: 1) Detail review of previous reports, maps, drawings, inventories, etc. 2) Stocktaking of different studies and investments ongoing and in pipeline in the region. 3) Undertake field trips to the identified hazard and risk areas to confirm desk studies, previous reports, hazard, vulnerability and risk maps, interpretation and gather supplementary data. 4) Assess the impacts/risk of flooding/debris flow