environment international |
Initial Environmental Evaluation, Appendix to the Northeast Regional Water Management Plan, Bangladesh Flood Action Plan 6 (IEE NERP FAP 6)Client: Government of the People's Republic of Bangladesh, Bangladesh Water Development Board, Flood Plan Coordination Organisation
Donor: Canadian International Development Agency
Consultants: SNC Lavalin International & Northwest Hydraulic Consultants Ltd., in association with Engineering and Planning Consultants Ltd., Bangladesh Engineering and Technological Services, Institute For Development Education and Action, and Nature Conservation Movement
Report written by: Dr. Sara Bennett, Mr. Mujib Huq, and Dr. David McLean.
The final version of this report was published in 1994
by NERP FAP-6. Published version is authoritative. Online version
(draft final dated May 1994) is for general information only.
Executive Summary (continued)
Most of the information presented here derives from work done as an integral part of the regional planning exercise, rather than from work done separately in the service of EIA/IEE. This reflects the nature of the regional planning exercise, which exhibited numerous features which are also typical of EIA/IEE.
The process and team were multi-disciplinary and multi-sectoral, with specialist studies in each discipline forming the foundation for the planning process. `Environmental' themes (best use, optimal resource utilization, future opportunities and threats, trade-offs, socioeconomic, gender, and age equity, cultural and institutional factors in resource management, and so on) played a central role in planning decisions. A public consultation programme (documented in detail in this volume) was undertaken to ensure that local input was incorporated. Also, the regional planning phase of the project included project-by-project IEEs of potential projects identified during the planning.
A master list of important environmental components (IECs) and generalized project activities were derived from information assembled during the regional planning process and these, augmented by project-specific additions as and when needed, was used for all the IEEs, both project and Plan. Assessment methodologies were also developed out of knowledge gained during the regional planning process.
At this level of assessment, impacts were bounded spatially in somewhat general terms, but in a hierarchy in keeping with the architecture of the Plan: for project benefits, nominal project area boundaries were used; for unintended effects of single projects, impacted areas outside project boundaries were added; and for cumulative effects, subregions, river systems, and the region as a whole were used.
Future-Without-Plan (FWO) Main Assessment FindingsOperation of the proposed Tipaimukh Dam/Cachar Plain Project on the Barak in India would moderate flows along the Kushiyara River and upper Surma River, decreasing monsoon flood levels and substantially increasing dry season flows. Impacts during reservoir filling could be even more significant. Ramifications for biophysical and socioeconomic environmental components include changes in monsoon cropping, reduced infrastructure and homestead flood damage, slower post-monsoon drainage, increased dry season in-channel fisheries habitat and improved migration access in the pre- and post-monsoon seasons, and so on.
The lower Kushiyara-Kalni River will continue to aggrade, as a result of upstream channel shifts, impacts of past loop cutting, and alteration of the river's flow regime. This will increase spills into the Baulai River and eventually lead to a partial avulsion from the Kalni River near Ajmiriganj towards the Baulai River. Pre-monsoon flood levels between Madna and Sherpur will increase, affecting 5,000 km2 of the central Sylhet Depression, including fourteen existing submersible embankment projects. Sediment deposition in the channel and adjacent floodplain will adversely affect fisheries and navigation. Similar but lower-magnitude changes are also expected on the Baulai.
The cumulative effects of the foregoing (Tipaimukh Dam plus aggradation on the Kushiyara-Kalni and Surma-Baulai) would be increased winter discharges and siltation along the Kalni River, with pre- and post-monsoon water levels higher by as much as 1.5 m at Markuli, but peak monsoon water levels higher by only 0.3 m. Ramifications include greater depth and extent of monsoon flooding, retarded post-monsoon drainage, and earlier and more severe pre-monsoon flooding of unprotected areas adjacent to the river.
Major avulsions appear to be either in progress or imminent on the Dauki-Piyain, Dhalai Gang, Jadukata and Someswari Rivers. However, channel avulsions are inherently unpredictable and could occur on any of the fans in the region over the Plan period. Avulsion from the Someswari down the Atrakhali would impact over much of the Kangsha River basin all the way down into the Central Basin, with flood conditions reduced in one area but intensified in other areas. The impact of the other ongoing and potential avulsions mentioned would be largely restricted to the fan areas.
The ongoing Systems Rehabilitation Project has proposed to raise, by over 1 m, submersible embankment heights in several projects in the Central Basin. NERP and SRP recognize that this increase in embankment design heights will result in embankment crests, including freeboard, at or above the 1:2 monsoon flood levels. The result will be increasing confinement of flows and sediment to the river channels, even if project areas are filled after the boro harvest. Post-monsoon drainage and fisheries could be adversely affected. [For these reasons, SRP will recommend that rehabilitation of these projects be deferred until after implementation of the NERP initiatives Baulai River Improvement and Kalni-Kushiyara River Improvement, which should decrease Central Basin pre-monsoon flood levels significantly.]
Future-With-Plan (FW) Main Assessment FindingsThe FCD projects in the Plan portfolio will profoundly alter the spatial and temporal distribution of water, and through these hydrologic impacts will produce significant beneficial and adverse impacts across the range of water-linked systems. The non-FCD projects in the portfolio, in contrast, have very limited potential for adverse impacts. Indeed, almost all of them are targeted to benefit either specific environmental systems that tend to be adversely affected by FCD development, or to enhance environmental quality directly, through non-structural or localized minor structural means.
FCD project impactsHomesteads on a total of 400 ha, occupied by 107,000 persons, and cultivation on 4,500 ha would be displaced by project works (embankments, structures, and larger channels). This is 0.9% and 0.3% respectively of total settlement and cultivated areas within project areas.
Homestead flood damage protection, raising existing homesteads, and creation of new homesteads would compensate and enhance regional homestead area. A total of 6,400 ha of formerly flood-affected homestead land, occupied by 1.4 million persons would be protected from flooding. This is 9.7% of the total regional homestead area of 65,000 ha, and 52% of the 12,000 ha of formerly flood-affected homestead area within project areas. A total of 700 ha of new homesteads would be created and existing homesteads raised using dredging and excavation spoil.
Within FCD projects, food production would change as a result of:
Water quality (as experienced by domestic consumers, fisheries, and wetlands) changes cannot be quantified, but would be affected in a number of ways. Drainage improvement would tend to improve water quality, by increasing flushing and flushed volume and duration, and decreasing stagnant water volume and duration. Flood control would improve water quality at some times and places, by eliminating flooding of domestic-supply tube wells and pit latrines for example, and worsen it at others, by decreasing flushing and increasing stagnant water volume and duration. The FCD-led increment in pesticide use (47 tonnes, or 9% of current usage of 530 tonnes) would contribute to water contamination, especially in low pockets surrounded by HYV cultivation. The FCD-led increment in fertilizer use (46,000 tonnes, 20% of current usage of 226,000 tonnes) would increase nutrients available to the openwater fishery, but could also aggravate eutrophication problems.
Navigation would be benefitted by river and channel excavation, and disbenefitted by the 48 closures of major and minor channels at embankments and across spill channels.
Wetland areas (i.e. fallow areas with sufficient moisture to support hydrophytic plants) would decrease, in winter by 7,000 ha or 5.7% of the regional total of 124,000 ha, and in summer by 50,000 ha or 11% of the regional total of 440,000 ha. About half (250 ha) of the region's remaining floodplain grassland (550 ha) could be adversely affected by Surma Right Bank Project. Hakaluki Haor, a key wetland site and mother fishery, would be adversely affected by sediment deposition as a consequence of the Manu River Improvement Project; Tangua Haor and Companyganj key wetland and mother fishery sites would be partially protected from sediment infilling by Jadukata-Rakti Project and Sarigoyain-Piyain Project respectively.
In some river systems, channelization of floodplain flows will increase river water levels, discharges, and velocities. These in turn may increase the cost of flood control measures (embankments will have to be higher and stronger) and infrastructure maintenance. If designs and maintenance are not upgraded enough, infrastructure may more frequently due to greater erosion and more frequent overtopping. When and where infrastructure fails, damage to crops, homesteads, and roads may be greater than in the unprotected situation because levels will be higher. Also, three areas in the region -- the Mogra basin, Hakaluki Haor, and the lower Sarigoyain River basin -- will remain both outside of flood control embankments and may be vulnerable to displaced flooding from Plan FCD projects, which could cause increased flood damage to crops, homesteads, and roads in these unprotected areas. Channelization, by raising river water levels, may in some cases result in improved conditions for river navigation and fisheries.
As for impacts outside the region, there would be no hydrologic or sediment impact on areas downstream, given conditions at the region's outfall. A possible exception could be transient effects due to turbidity from dredging. Pesticide loadings of regional drainage flows would increase, proportional to usage increases. Migrating waterfowl populations will be adversely affected by the overall reduction of winter wetland areas and adverse impacts on Hakaluki Haor. This could be somewhat compensated by positive impacts on Tangua Haor and Companyganj area.
Non-FCD Project ImpactsNon-FCD Plan projects -- many of which mitigate, compensate, or enhance environmental components adversely impacted by the FCD projects -- address rural and urban water supply, sanitation, and rural hygiene education; biodiversity and surface water quality management; aquaculture; ground water management; applied research to improve farming systems in the deeply flooded area; openwater fisheries engineering and management; improvement of homestead platforms and village afforestation and habitat restoration to control wave erosion and generate biomass inputs (fuel, building materials, etc.) to village systems; navigation; flood warning; and institutional strengthening in selected areas. Impacts are generally relatively straightforward and relate closely to intended project benefits. Some of these projects exhibit specific possible adverse impacts, all of which appear to be mitigable or otherwise manageable with reasonable effort. Examples of such possible impacts include displacement impacts associated with minor construction, regressive socioeconomic equity impacts, and intensification of social conflicts over resource management and control.
EX-PLAN CUMULATIVE IMPACTSPlan impacts will act in a cumulative manner with the expected impacts of ongoing large-scale processes external to the Plan. Such processes include population growth, urban infrastructure development in and in-migration to urban areas, climate change, energy production and consumption trends, and increasing contamination of water supplies from domestic, industrial, and agricultural discharges.
Plan implementation is expected to contribute to developmental trends which are thought capable of contributing indirectly to slowing of population growth. This conclusion rests on the interpretation that population growth rates are highly dependent upon parents' perceptions of ideal or desired family size; perceived insecurity in old age; and acceptance of and access to effective family planning. These factors are in turn strongly influenced by income, child mortality, women's status, and access to family planning services (World Bank, 1992). All but the last (which clearly lies entirely outside the ambit of water management planning) would be impacted by Regional Plan implementation. This model is not, of course, universally accepted. Under a neo-Malthusian scenario, which NERP does not endorse, increasing food production and public health improvements, as would be achieved under the Plan, simply fuel further population growth. In practice, a population growth rate was applied as a boundary condition to the regional water management planning exercise. That is, an expected growth rate was assumed for the region, to be taken into account in formulating the Plan. This amounts to a linearization of the Plan-population growth relationship.
Plan implementation is expected to accelerate urban infrastructure development and in-migration to urban areas. Many urban areas in the Northeast Region, and in Bangladesh as a whole, are located in areas which are vulnerable to flooding. Thus provision of flood control to urban and peri-urban areas could paradoxically increase total flood damage, integrated over floods of all recurrence intervals: with less risk from more frequent, lower magnitude floods, people will increasingly settle and invest in areas which remain vulnerable to less frequent, high magnitude floods. In addition to this, however, flood control may act to reduce hidden costs associated with flood exposure, such as the cost of low productivity due to low investment. At the level of FCD project feasibility studies, there will be a need to investigate both the direct and hidden flood damage costs associated with a range of project and urban development scenarios.
The air temperature and sea level components of anthropogenic climate change will not be perceptible over the 20 year period of the Regional Plan, (i.e. the presumed rates of increase of both are too slow to be discerned over this short time interval), but future rainfall trends could be of significant magnitude, judging from the tendency observed over recent decades for increasing rainfall and increasing rainfall variability. Impacts of a cumulative nature (Plan + increasing rainfall) relate mainly to increased river discharges and water levels (e.g. embankments + increased rainfall), leading to morphologic changes (wider channels, aggradation/degradation waves propagating through the system, and increased channel instability and type switching). Other aspects of Plan interventions would tend to mitigate affects of rainfall increases: drainage improvement could reduce system drainage overloading, habitat conservation and restoration could ensure that development options (swamp forest) suitable for the new conditions are preserved, and so on. Increasing rainfall would also have important environment-on-project impacts: water management could become increasingly difficult, infrastructure maintenance increasingly costly, and the relative feasibility of various water management and development options could shift. Drainage improvement would increase in importance relative to flood control, and fisheries and swamp forest could become viable over greater areas as damage to rice crops reduces yields. Decreasing rainfall would lead to impacts opposite in sign and type.
Plan implementation would impact regional patterns of energy production and consumption. Energy supplies in the region derive from a wide range sources, many of which are inter-related: a great variety of biomass fuels from natural sources; animal draught power; human muscle power; solar energy; and fossil fuels. Changes in fodder and biomass fuel production as a result of Plan implementation have already been mentioned. Fossil fuel usage, of particular interest because such they are non-renewable, contribute to environmental pollution, and tend to be imported, and increasing dependence on them increases external dependence, economic unsustainability, and public health and ecological problems. Direct increases in fossil fuel usage as a result of the Plan would however be very small, with direct fuel consumption for pumped irrigation increasing by 1%. Indirect increases include that for manufacture of fertilizer, for which usage would increase by 9%.
Plan implementation would impact regional water quality through increased agrochemical usage (mentioned above), and through direct measures to manage contamination sources and water supplies.
SUSTAINABILITYA sustainability analysis of Plan interventions indicates a number of areas for concern. Some of the impacts associated with FCD infrastructure may be or will be irreversible. These impacts include in particular the impacts of Manu Diversion Project and Surma Right Bank Project on biodiversity values at Hakaluki Haor and Bara Haor. Plan FCD projects have a net negative impact on the openwater fishery, a system which is already under considerable stress; some of the Plan non-FCD projects address this area, but their success is not a foregone conclusion. Production, management, and consumption of biomass materials (for example, rice straw and husks, manure for energy, wetland products) for fodder, fertilizer, building materials, is benefitted by the Plan, but more systematic management improvements may be necessary to ensure that local needs are met sustainably.
ENVIRONMENTAL MANAGEMENT PLANThe emphasis at the IEE, pre-feasibility, level is on identifying issues and options, to guide the detailed design of specific EMP measures as part of programme and project feasibility studies.
The architecture of the Plan portfolio includes mitigation of adverse FCD impacts by some of the non-FCD projects. Thus acceptable environmental performance is contingent upon implementation of the portfolio in a balanced and correctly phase manner.
Important areas for environmental management will include: management of displacement impacts, including cash compensation and resettlement activities, and raising and construction of homesteads from spoil; proper management of dredging activities; mitigation and compensation of adverse openwater fisheries impacts; compensation of wetland and biodiversity impacts through regional biodiversity enhancement; and attention to socioeconomic equity and conflict issues in FCD projects, and in projects dealing with common-property and government-owned fishery and wetland resources.
REVIEW PROCESSThis document is subject to review procedures described in the FPCO and MOI Guidelines for Environmental Impact Assessment (1992), which involve review activities by a Project Review Committee, composed of proponent representatives and by the Department of Environment, which has final authority to review and approve EIAs for projects in Bangladesh.
| go to chapter 1
This web page (previously international environment & development professional's home page) created by water environment international. All site pages (c) wei. Last modified 26 Aug 2002 . Comments? Problems? Email firstname.lastname@example.org
You are visitor since 25 Aug 98