Initial Environmental Evaluation, Appendix to the Northeast Regional Water Management Plan, Bangladesh Flood Action Plan 6 (IEE NERP FAP 6)

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.
 

Table of contents Acronyms and abbreviations Glossary of terms Ch.  1: Introduction Ch.  2: Regional Plan alternatives Ch.  3: Regional Plan description Ch.  4: Existing environment description Ch.  5: Scoping, public consultation, IECs Ch.  6: Biophysical response & impact processes Ch.  7: Assessment methods, data, assumptions Ch.  8: Future without Plan impact assessment Ch.  9: Regional Plan impact assessment Ch. 10: Cumulative impacts & sustainability Ch. 11: Environment management plan References

Executive Summary Overview This Appendix presents the Initial Environmental Evaluation of the Northeast Regional Water Management Plan, which is the final product of Phase I (1991-93) of the Northeast Regional Water Management Project (NERP). NERP is Component 6 of the Flood Action Plan (FAP) and one of five regional water management studies within the FAP. The purpose of this IEE is to characterize the potential environmental impacts of Plan implementation, at a level of information and analysis consistent with the Plan itself. To this end, all potentially significant impacts are identified and characterized to an indicative level on the basis of available secondary data supplemented with rapid rural appraisal and case study field data, with reference to prior experience in the region and, as reported in the literature, in other settings. At this stage, environmental management issues and options are identified and discussed but an Environmental Management Plan is not delineated in detail.

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 Findings

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 Findings

FCD project impacts

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:

• Increased annual paddy production by 570,000 or 10% of present regional annual production of 5.6 million tonnes, mainly by reducing flood risk and damage to crops and altering land types;
• Increased annual production of other food crops by 123,000 tonnes, 12% of current annual production of 1.0 million tonnes;
• Fodder production as a second or third crop on 26,000 ha;
• Increased homestead agricultural production (spices, fruit trees, vegetables, livestock, etc.) on 7,800 ha (net of homesteads protected from flood damage, created and raised with spoil, taken from project works);
• Decreased annual openwater fish production by 10,600 tonnes or 11% of current regional annual production of 96,000;
• Increased annual aquaculture fish production by 1,600 tonnes (counting only effects of flood risk and damage averted) or 8.8% of current regional annual production of 18,000 tonnes; and
• Decreased winter grazing area (winter fallow dry lands) by 54,000 ha or 7.0% of the current area of 779,000 ha.

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 Impacts

EX-PLAN CUMULATIVE IMPACTS

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.

SUSTAINABILITY

ENVIRONMENTAL MANAGEMENT PLAN

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 PROCESS

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