--  R e p o r t   S u m m a r y   --

Background

• Na Hang Nature Reserve was established in 1997 specifically to protect the largest surviving population of the globally critically endangered Tonkin Snub-nosed Monkey, thought to number under 130 in 1994.
• Officials in Tuyen Quang say that the first proposal for a dam on the Gam River was put forward 25 years ago.
• Electricity of Vietnam (EVN) undertook a pre-feasibility study of a proposed dam on the River Gam in 1997.
• The site has also recently been re-evaluated as part of the National Hydropower Study being undertaken by a consortium composed of SWECO International, Statkraft Engineering and Norplan AS.
• The National Hydropower Study included Na Hang on a shortlist of 16 preferred sites in Vietnam, but neglected to acknowledge the presence of the Na Hang Nature Reserve during its initial environmental screening of the site.
• The proposed site for the Na Hang Dam, below Pac Ta Mountain, would impound an area of water of 57 square kilometres, forming a long, narrow reservoir extending over 30 kilometres up the valley of the River Gam and its tributary valleys. The dam would have an installed capacity of 300 megawatts.
• In 1999, Electricity of Vietnam prepared the Terms of Reference for a full feasibility study of a dam at Pac Ta.
• Any dam would require a formal Environmental Impact Assessment under the Law on Environmental Protection.
• The dam will potentially have significant impacts on the natural resources of the area and on the local people including those to be resettled and those who remain. This report discusses these impacts.

The impacts of the dam on Na Hang Nature Reserve

• It is estimated, on the basis of maps provided by SWECO, that the construction of a dam with a full supply level of 120 metres will lead to the inundation of approximately 220 hectares of the reserve along the banks of the Gam and Pac Vang rivers.
• This is only a small portion of the total northern part of the reserve. However, it lies immediately adjacent to or within the area known to harbour the Tonkin Snub-nosed Monkey and the Francois' Langur. It is, therefore, a critical part of the reserve.
• The Pac Vang River to the north of the reserve can currently be crossed by the Tonkin Snub-nosed Monkey, giving access to the relatively undisturbed area to the north. The flooding of the valley would effectively cut off this area to the monkey and reduce the potential of any new habitat corridor.
• The potential impacts of the dam construction on the Tonkin Snub-nosed Monkey relate primarily to loss of habitat, increased disturbance, and habitat fragmentation.
• The exact impact on the Tonkin Snub-nosed Monkey is difficult to evaluate, but it appears that it will be minimal only if the monkeys are confined to the highest areas of high quality forest. Otherwise the dam will reduce and restrict the core area of habitat used by this species.
• The flooding of the valley will result in the submergence of the riverbank. This is a potentially important edge habitat of significance for wading birds, herons etc.
• Other impacts include:
  • the inundation of limestone caves important for bats and possibly other mammals
  • improved accessibility for people engaged in illegal activities such as clearing for timber or agricultural land
  • felling of timber in the inundation zone will increase disturbance in the reserve
  • construction workers may provide a market for illegal forest products, especially wildlife
• Countering these effects, if the resettlement programme is effective then there will be fewer people resident in this valley, reducing human pressure on the forest there.
• Translocation of Tonkin Snub-nosed Monkeys is undesirable given the limited knowledge of the primate’s ecology.

Other impacts

• Also given consideration are:
  • other physical impacts (including geology, soils, erosion and sedimentation)
  • ecological impacts (including climate, fisheries, wildlife and forests)
  • impacts on human use values (including agriculture, navigation, power and flood control
  • impacts on quality of life (including socio-economics, resettlement, culture, aesthetics and public health)

Recommendations

• The report concludes that the significance of some predicted environmental impacts and uncertainties about other impacts demonstrate the need for a full Environmental Impact Assessment.
• This assessment must:
  • assess the demand for construction materials and likely sources
  • establish the nature and extent of riverine habitats and consider the issue of bank side erosion
  • establish the likely climatic effects of the reservoir
  • assess the fishery value of the River Gam
  • establish the current status, ecology, and range of the Tonkin Snub-nosed Monkey
  • establish the habitat and distribution of the Francois' Leaf monkey within the reserve
  • establish the likely impact of the dam on other threatened species within the Nature Reserve
  • assess and map the forest types in the area to be inundated
  • calculate the likely additional agricultural output arising from downstream irrigation
  • consider the size and housing of the construction workforce
  • assess cultural/historical/archaeological resources in the area

Note

• Since the preparation of this Preliminary Environmental Impact Assessment, the Government of Vietnam approved dam construction a site further down stream, below the confluence of the Gam and Nang Rivers.
• The new dam site will impound a substantially larger area of water than the Gam River dam evaluated during the study described here. Preparatory construction began in the second half of 2002.
• PARC commissioned a Supplementary Environmental Impact Assessment of the new site in reaction to fears that environmental concerns were still not being properly addressed in the dam preparation (PARC 2002, Supplementary Environmental Impact Assessment of the Na Hang Dam: Final Report and Appendices).

Table of contents

1. Introduction
2. The Development and its Environment
3. Stakeholder Attitudes
4. The Impacts of the Dam on the Na Hang Nature Reserve
5. Preliminary Environmental Impact Assessment
6. Findings, Recommendations and Conclusions
7. Alternative Development

The full report can be downloaded at the top of the page

© PARC Project
Creating protected areas for resource conservation using landscape ecology

updated:
15/10/03