Delivered at The World Bank's Environmentally and Socially Sustainable Development 5th Annual Meeting, October 10, 1997

Introduction

Most of the papers presented today have dealt with the assessment and problems associated with conserving and preserving freshwater ecosystems throughout the world. The primary focus of these papers has been the need to identify and establish an awareness of these ecosystems to enable consideration of the resources in planning water resource developments. Little attention has been given in preceding presentations as to how these issues can actually be integrated into a water resources development plan.

What is Mainstreaming?

As we have discussed in previous presentations, AMainstreaming@ has several meanings relative to the subject at hand. First, AMainstreaming@ refers generally to the incorporation of a basic concept or issue into the general process of planning and developing a resource development. In terms of a water resources development, mainstreaming of freshwater biodiversity is analogous to the necessity for considering the size and configuration of a spillway or the soundness of the geological formations that will serve as a foundation for a dam. Thus, as plans and designs are developed, the goal of Amainstreaming@ aquatic biodiversity is that consideration of freshwater biodiversity is equivalent to the consideration of other engineering factors such as hydrologic regime, geological conditions or spillway size. A second, more subtle meaning of AMainstreaming@ is particularly aimed at maintaining the biodiversity found in wetlands, streams and rivers.

Classic Water Resources Development Planning

Classically, planning and design of a water resources development is based on a relatively limited set of criteria set forth by the developer in response to requirement for obtaining the highest return possible on an investment and meeting the requirements of the funding agency. Normally, the planning process starts with the definition of the objective of the project (i.e. power generation, irrigation, navigation, flood control, or domestic water supply) with the imperative that the cost of development of the project is as low as possible and the economic benefit is as great as possible. Given the objective and the imperative, engineers embark on a program of selecting an appropriate location (generally in proximity to the user) where the hydrologic, topographic and foundation conditions are conducive to development. The structural components of the project are then selected (e.g. type of dam, size of spillway, location of power house or intake structure) and appropriate layouts and designs are identified which enable optimum use of the resource for the single objective formulated by the developer. Nearly all of the considerations involved in planning or designing the project are driven by the singular objective of the project and the components necessary to achieve that objective. To accomplish this, considerable background or baseline information relative to each component is obtained. For example, the selection of dam type is based upon a thorough understanding of the topography of the selected site, foundation conditions, and availability of construction materials. Similarly, selection of the spillway configuration and design is dependent upon a sufficient understanding of the hydrologic regime.

Only after much of the planning has been completed is consideration of environmental issues brought into the planning effort. Frequently, this occurs only after a Afeasible@ project concept is selected. The major problem with this is that consideration of proposals to Amitigate@ or minimize adverse effects of the project to freshwater ecosystems or other environmental resources, are viewed as hindrances creating considerable additional costs to development of the project. The Afeasibility@ of the project is normally based on Aoptimum@ development (i.e. B/C ratio is maximal) of the resource and incorporation of measures to protect either the freshwater ecosystem (fish ladders, etc.) or the terrestrial ecosystem (buffer zone, etc.) are considered a less than optimum development.

New Paradigms In Project Planning

A goal of this conference, and others similar to it, is that consideration of environmental factors that become an integral part of project planning and are fully recognized in the definition of an optimum project development plan. In economic terms, the optimum development must include consideration of environmental protection measures as part of the overall benefit/cost ratio evaluation. When this occurs, consideration of measures to protect aquatic biodiversity will become a part of the Amainstream@ of project planning.

In reality, this goal requires the formulation of a new paradigm for planning water resource developments: That is that consideration of Aenvironmental factors@, in particular, freshwater biodiversity, is elevated to the same level of consideration as is the geologic conditions at the proposed project location. By doing this, the single objective motive for developing a project is expanded to a Amultiple@ objective motive in which the benefits of the project are measured not only by the output of the project in economic return but also in environmental terms. AFeasibility@, in turn, is determined not only on the basis of both long term economic return relative to the funds required to construct the project, but also on the basis of long term protection of the ecosystem.

Ideally, consideration of potential environmental effects, particularly to aquatic resources, must be considered as part of the conceptual design of any water resources development. This consideration should begin the selection of the site for potential development. As with the engineering evaluation, potential effects to aquatic (and terrestrial) environments may be easily integrated into the evaluation process. Various site selection methods have been used to evaluate potential sites that include consideration of environmental effects. Each of the methods requires background information sufficient to identify potential environmental effects just as background information is required to evaluate the site from an environmental perspective. Such evaluations should become one of the criteria for selection of an appropriate site for development. Typically, ARed Flag@ analyses are used early in the engineering evaluation of a proposed site. A similar analysis of a potential site might also be conducted from an environmental point of view. Existence of habitats for endangered species, unique or rare assemblages of fish, plants or animals, and other characteristics of a site are prime candidates for ARed Flag@ analyses incorporating environmental considerations. Other, more comprehensive evaluation protocols are also available that enable consideration of environmental parameters in determining the suitability of a site for development.

Anticipation of Potential Effects

Once a site has been identified, information necessary for a prefeasibility evaluation of the site by an engineering group is obtained. The evaluation addresses foundation conditions, hydrology, topography information and a preliminary layout of the site is developed. At this time in the evaluation, more detailed information relative to aquatic environments may also be obtained. Based on the available information, including data collected previously and new information regarding the site, potential effects of the project can be identified. As with engineering evaluation of a site in which both structural and operational characteristics are evaluates, the potential effects of the structure and operation of the project must be considered in evaluating the site relative to environmental concerns.

Whereas a preliminary engineering evaluation will focus primarily on the location of the project structures (albeit, characteristics of the area upstream from the construction site are considered), an evaluation of the site relative to potential effects to the aquatic system must focus primarily on both upstream and downstream characteristics and the linkage between the two areas. Such information is necessary to determine the potential effects of the project and enable selection of appropriate measures to avoid or minimize the effects.

Potential Upstream Impacts

Upstream from a construction site, potential effects of a project to the aquatic ecosystem will affect physical, chemical, and, subsequently, biological characteristics. Generally, the direct impacts of a water resources development affect physical and chemical characteristics which in turn affect biological characteristics. Physical and chemical impacts of an impoundment are relatively straightforward and include conversion of a riverine environment to a lacustrine environment, concurrent changes in the oxygen profile of the water body, changes in the nutrient content of the water, and changes to a wide variety of other physical and chemical properties. Understanding of the physical and chemical changes that will occur in an impoundment, leads to an understanding of the potential changes that will occur to the biological communities inhabiting the affected river reach. The basic changes involve conversion of the community from one which is dominated by riverine species to a community that is dominated by species adapted to life in a lacustrine environment.

The significance of these changes depends entirely on the significance of the existing conditions. From a purely economic point of view, many species that require flowing water for survival are frequently significant elements of the local economy. Migratory fish, for example, may provide a significant resource for subsistence or market income to local residents. Similarly, certain invertebrate species, such as molluscs and crustaceans, contribute significantly to a local economy. Determination of the potential for these species to survive in a lacustrine environment and the relative importance of these species in the local economy, comprises the kinds of information necessary to evaluate the significance of the impact of the proposed development.

From an ecological point of view, the diversity of species present in the affected river reach is an indication of the relative importance of the reach to aquatic biodiversity issues as a whole. The continued existence of economically important species is often dependent upon the continued existence of available food resources and the inability of a forage species to survive in the altered environment, may result in the loss of economic species. Also, loss of suitable habitat could lead to threatening or endangering the continued existence of the species.

While the above discussion focuses on the potential adverse effects of a water resource development, the significance of these adverse effects can be ameliorated to some extent by also considering potential benefits to the aquatic system. Although many species are not capable of adapting to a lacustrine environment, other species will greatly benefit from the expansion of the available habitat afforded by the impoundment. Projection of the aquatic community that might become established in the impoundment is an additional factor in the evaluation of the effects of a project. The aquatic community that becomes established in an impoundment could become a significant economic resource for the local community, as has been the case in numerous projects throughout the world. Consequently, consideration of the potential benefits to the aquatic ecosystem, as well as the potential losses, should be incorporated into the project evaluation. Potential Downstream Impacts

Throughout the planning process, consideration of the potential effects downstream from the project is equally important, if not more so, than the consideration of potential effects in an impoundment area. Protection of riverine species in the tailwater and further downstream is vital to development of a project which is compatible with maintenance of aquatic biodiversity. Again, the direct effects of a project to the downstream environment are primarily to physical and chemical factors with biological effects occurring as a result of changes in physical and chemical characteristics.

The primary physical effect of a water resource development is the change to the hydrologic regime. Some modification of the annual hydrologic regime is inevitable and results from the storage of water in the impoundment, regardless of the operational mode of the project. Changes in the hydrologic regime range from slight reduction in annual flow fluctuations and reduction in the volume of water, to major flow fluctuation on a daily basis, and, in some cases, elimination of flow in some reaches of the river on a permanent.

Another physical effect is a modification of the temperature regime, with the overall effect resulting from the storage of water in the impoundment and a shift in the timing of the occurrence of maximum and minimum water temperatures in the tailwater due to the thermal consequences of the larger volume of water in the impoundment. Such changes in the thermal regime can result in significant changes in the types of species that can inhabit the tailwater area.

Potential changes in water quality include changes in the dissolve oxygen concentration regimes, changes in nutrient concentrations, and the introduction of other dissolved chemicals resulting from limnological processes in the impoundment. Another factor which may occur is the occurrence of supersaturated nitrogen concentrations in the tailwater that may occur when water is spilled from the impoundment.

The potential physical and chemical changes, in turn, may result in considerable change in the biological communities downstream from the project. These changes may be the direct mortality resulting from insufficient water or dissolved oxygen or the changes may be delayed due to interruptions to the reproductive cycles. To fully understand the effects that may be realized in the downstream reach, sufficient information is necessary to fully understand how the existing community responds to, or makes use of, the existing environment.

In planning a water resources development, engineers have a number of options available to adjust the layout of the project to accommodate various technical characteristics of the project site. Consideration of these options are integrated early into the planning process and are readily incorporated into estimating the cost of the development. For example, a variety of options are available to prevent leakage from the dam. Various types and configurations of spillway gates and other hydraulic equipment are available to enable efficient handling of the water. The necessity for evaluating and integrating these various options in the planning process is basically what defines the Amainstream@ of project planning. Consideration of options to protect aquatic organisms, on the other hand, is most often considered a nuisance and, thus, considered an unnecessary add-on to the overall project cost. When consideration of environmental factors becomes a part of the Amainstream@, the necessity for evaluating options to protect aquatic organisms is no longer a nuisance but an integral part of project planning.

A variety of options are available to protect aquatic ecosystems both upstream and downstream from the project. Opportunities to protect aquatic biodiversity upstream and downstream from the project include both structural and operational components. The following discussion presents a brief listing of some of the opportunities that are available and some of the ramifications associated with each opportunity.

Opportunities to Modify Project Layout to Protect Aquatic Resources.

Opportunities to modify the project layout or incorporate specific structural measures to protect aquatic resources are most often rejected by engineers and developers because they are readily identified as additional add-ons to the overall cost of the project. However, some of these opportunities are most efficiently incorporated early in the planning process and, when included, may be most effective in avoiding potential adverse effects to aquatic habitat.

Opportunities to Protect Upstream Aquatic Resources

Fish Passage. One of the more common effects of water resources developments is the blockage of fish movement through the project site. This includes both upstream and downstream movement to and from spawning areas or to and from foraging areas. A variety of fish passage facility designs have been developed which are effective and include artificial channels for movement of fish through the project site (fish ladders), elevators, and trap-and-haul schemes. Selection of an appropriate design for fish passage facilities is highly dependent upon the behavior of the fish, the size of the population moving through the project site, and the seasonal movement of fish within the river. Specific requirements of the affected species will dictate the most appropriate design for the facilities.

Incorporation of a fish passage facility into the overall design of the project facilities may also affect the relative layout of other components of the project. Consequently, a decision to incorporate fish passage facilities early in the planning process will lead to facilities which meet the requirements of the fish and be compatible with other components of the project. For example, the location of the intake and draft tube relative to the dam may be designed to incorporate the hydraulic requirements for an effective fish passage facilities. By incorporating fish passage facilities into the project layout, the overall cost of the facilities may be reduced and the effectiveness improved.

Barrages to Protect Parts of Reservoir. Other structural modifications that may be adopted to protect aquatic communities upstream from the project site include construction of barrages in arms of the impoundment to reduce daily and/or annual fluctuations in water level. For some species, specific habitat conditions for spawning and foraging include relatively stable water levels, in some cases, for extended periods of time. For example, species that spawn in water that is less than 1 - 2 m deep are inhibited from spawning when water level fluctuates by that much on a daily basis due to peaking operation of the project. In such a situation, barrages may be constructed in arms of the reservoir to maintain a more constant water level in the arm and provide suitable habitat for those species.

Clearing of Reservoir Area. In many areas, clearing all vegetation in the reservoir area prior to filling of the impoundment is considered standard practice. However, this option should be considered in detail before it is incorporated into the construction plan. As has been shown in a variety of projects, clearing of the reservoir area was necessary to prevent the occurrence of anoxic conditions in the impoundment due to decay of the organic materials. However, in other circumstances, the need to clear the reservoir of vegetation has been shown to be unnecessary. Generally, the volume of vegetation in the reservoir should be compared with the total volume of the reservoir and the residence time of water in the impoundment. Unless it is shown that removal of vegetation is necessary to prevent anoxic conditions in the reservoir, allowing woody vegetation to remain in the impoundment zone results in the provision of suitable habitat for a variety of lacustrine vertebrate and invertebrate species. The decision to clear vegetation within the impoundment zone should be made on the basis of both the potential for generating anoxic conditions in the impoundment and the habitat requirements of fish and invertebrate species that are likely to become established in the impoundment.

Opportunities to Protect Downstream Aquatic Resources

As with opportunities to protect aquatic ecosystems upstream from the project site, a variety of structural modifications are available for incorporation into the conceptual design for the project that enable protection of the aquatic ecosystem downstream from the project site.

Reregulating Dam. One of the more common modes of operation, particularly for hydroelectric projects is peaking in which water is released through the power station for relatively short periods during the daily cycle. In some situations, peaking mode results in the complete dewatering of the tailwater for extended periods of time on a daily basis. Obviously, with no water, aquatic organisms are unable to survive in such a situation. To reduce the impacts of fluctuating flow, a secondary dam may be constructed downstream from the main dam to reregulate the release to a more constant level. The reregulating dam and impoundment is then operated in a manner to maintain a more constant flow in the river downstream from the project.

Fish Passage Facilities. Incorporation of fish passage facilities into the conceptual layout not only protects the aquatic community upstream from the project but also provides protection to the aquatic community downstream from the project. The rationale for incorporating of fish passage facilities into the conceptual design to protect downstream resources is essentially the same as that for protecting upstream resources.

Temperature Regulation. As mentioned previously, a water resources development will affect the temperature regime of the tailwater and downstream reach because of the retention of water in the impoundment. If the impoundment stratifies, an intake structure situated below the level of the thermocline will result in the release of cold water to the tailwater. Placement of the intake near the bottom of the impoundment, or at least below the minimum anticipated water level, is done both because the cost for building an intake near the surface is frequently greater and because hydraulic conditions at the face of the intake structure affects the efficiency of water flowing through the water conveyance structures. The consequence is that water temperature in the tailwater will be considerably lower than under natural conditions. In situations where the intake is located near the surface of the impoundment, warmer water is released to the tailwater. In either case, the temperature regime of the tailwater is modified and will generally exhibit a much narrower amplitude in seasonal variation.

To minimize this effect, modifications to the layout and configuration of the intake structure may be considered. A measure that is frequently considered is the incorporation of a multiple level intake structure which allows selective withdrawal of water with appropriate temperature from the impoundment. Other measures include positioning the intake as near the surface of the impoundment as possible, or at least within the zone of the expected epilimnion, where water that is exposed to atmospheric conditions is released through the conveyance structures. To minimize potential effects of an altered thermal regime and incorporate appropriate design characteristics, specific criteria for the design of the intake must be established as an a priori condition of the project and incorporated early in the planning process.

To establish the need for and location of an appropriate intake structure, it is first necessary to determine the temperature requirements of the organisms in the tailwater and then project the effects of the impoundment on those requirements. A variety of simulation techniques are available to assist in the determination of the effect of the project on the temperature regime. Results of these analyses may then be compared with the existing temperature regime to enable estimation of the potential effects to the aquatic community in the tailwater area.

Oxygen Concentrations. As with the temperature regime, a common problem at water resources developments is the release of water with low concentrations of dissolved oxygen. This situation occurs when the intake structure releases water from the hypolimnion and the hypolimnion becomes anoxic, or at least the dissolved oxygen concentrations are depressed, during the period when the impoundment is stratified. Among the options available to prevent release of water with low dissolved oxygen concentration, positioning the intake structure at a level within the anticipated epilimnion will minimize the potential for releasing water with low dissolved oxygen concentrations to the tailwater. Other mechanisms include installation of air or oxygen injection systems in the penstock or into the turbine equipment and installation of barrages in the tailwater to provide hydraulic aeration of the water.

Determination of the potential that a particular impoundment is likely to result in release of water with low dissolved oxygen concentrations should be made early in the planning process. As with evaluation of the temperature regime, a number of analytical procedures are available to evaluate the need for and effectiveness of alternative measures to improve dissolved oxygen concentrations.

Gas Supersaturation. Nitrogen gas supersaturation is frequently encountered at high head projects or at projects where large volumes of water released to the tailwater area. Conditions that give rise to gas supersaturation are linked almost exclusively to the relationahip between the volume of water released, the configuration of the spillway, and the configuration of the plunge pool into which water is released. Basically, gas supersaturation occurs when air is entrained by plunging water and is carried to depths of ten or more meters into the plunge pool. At that depth nitrogen gas dissolves into the water and when it returns to the surface, the concentration is greater than saturation. Supersaturated concentrations of nitrogen gas causes what is referred to as Agas bubble disease@ in fish and other aquatic organisms, a condition similar to the bends in humans. Such conditions frequently arise where a number of water resources projects are developed in a Acascade@ arrangement along a river course or where large volumes of water are released into the tailwater.

Preventing the occurrence of this condition is relatively simple, but it needs to be considered early in the planning process. Commonly, conditions which lead to gas supersaturation are eliminated by either changing the angle at which water enters the plunge pool or reducing the depth of the plunge pool. Where large volumes of water are involved, use of multiple gates to spread the spill across the river will serve to reduce the depth of penetration of water into the plunge pool. Use of an outlet structure that converts spilled water into a Aspray@ will reduce the penetration of water into the plunge pool. Also, use of Aflip buckets@ at the end of a spillway or other design features that cause water to enter the plunge pool at a more horizontal angle will prevent supersaturation of gas in the tailwater. Anticipation of the potential for gas supersaturation and incorporation of an appropriate spillway/plunge pool design early in the planning process is essential for avoiding this potential impact.

Opportunities to Modify Project Operation

All water resource developments are planned with some type of operating mode in mind. Hydroelectric projects, for example, be operated on a run-of-river, store-and-release, or peaking basis. Water supply projects for irrigation or domestic use are generally designed to operate on a store-and-divert basis. Navigation projects are designed to maintain water depth, and thereforeare operated on a run-of-river basis, while flood control projects are designed for store-and-release operation. Opportunities for adopting an operating mode that protect aquatic resources depend primarily on the habitat requirements of the aquatic organisms. Given the habitat and flow requirements of the aquatic organisms, appropriate operating criteria may be established to meet both the needs of the aquatic organisms and the needs of the developer.

Opportunities to Protect Upstream Resources

Operating modes to protect aquatic resources in and upstream from the impoundment are relatively limited. As discussed above, many lacustrine species require relatively stable water levels, at least during certain periods, in order to reproduce or forage effectively. Consequently, adoption of a run-of-river operating mode is most effective in protecting upstream aquatic organisms. Operation of a project on a seasonal store-and-release basis is frequently adopted for projects which are designed to serve as a water source for domestic or irrigation use. In such situations, water level in the reservoir fluctuates on a seasonal basis and is relatively benign to aquatic ecosystems because water level fluctuation in the impoundment is relatively slow and aquatic organisms are able to adapt to the fluctuation.

Many hydroelectric projects are operated on a peaking basis. Water level fluctuation associated with peaking operation is generally considered harmful to aquatic organisms when applied over a long period of time. Modification of peaking operation mode by reducing the range of operation or by seasonally adjusting the operation to maintain more constant water levels at certain critical times of the year can be adopted to minimize the potential impacts of peaking operation to aquatic resources in the impoundment.

Opportunities to Protect Downstream Resources

More dramatic effects of various operating modes are generally exhibited downstream from a project. A number of opportunities to modify operation of a project have been devised to protect downstream resources. The selection of an appropriate operating modes is highly dependent upon the hydrologic regime required by aquatic organisms inhabiting the river downstream from the project. Some of the opportunities for selecting an operating mode that protects aquatic habitat downstream from a project are presented below.

Run-of-river Operation. In most cases, aquatic organisms inhabiting the river downstream from a project can be protected most easily by adopting a run-of-river operating mode. Run-of-river operation implies that the overall hydrologic regime for the reach downstream from the project most closely resembles the natural hydrologic regime because outflow from the impoundment is equivalent to inflow to the impoundment on an instantaneous basis. Such an operating mode is commonly associated with navigation projects and some hydroelectric projects. However, selection of a run-of -river operating mode is in direct conflict with the basis purpose of a project. Projects designed for irrigation or domestic water supplies, by definition, result in modification to the hydrologic regime storing water to be withdrawn from the impoundment. For such projects, run-of-river operating mode is not appropriate.

Minimum Release. For most projects, including hydroelectric and water supply projects, maintenance of a constant minimum release to the downstream reach is an effective way to protect aquatic organisms inhabiting the river downstream from the project. For hydroelectric projects that are operated on a peaking basis, can be required to maintain a minimum release to the tailwaterflow throughout the 24-hour period. Such a release can effectively reduce the effects of flow fluctuation or dewatering of the tailwater on aquatic organisms while enabling the project to operate to meet peak power demands in the system. A wide variety of analytical techniques have been developed to evaluate how much water is needed to maintain aquatic organisms in the downstream reaches.

Although the overall benefit to the project relative to power generation during peak demand periods is reduced, the loss of revenues can be at least partially offset by using the release for base-load generation. Benefits to the aquatic community in the tailwater reach, including the economic benefit of protecting economically important aquatic species may also be incorporated into the benefit/cost analysis further offsetting the loss of revenues due to a minimum release requirement.

Similarly, maintenance of a constant, a requirement for a minimum release from water supply projects will reduce the amount of water available for withdrawal. The loss of waer for withdrawal and the associated reduction in potential revenues may be offset by installation of power generating equipment in the outlet.

Other Mitigation Opportunities

Regardless of whether various structural and operational opportunities are incorporated into the project, development of a project will unavoidably cause some disruption to the habitats of auatic organisms. In the absence of available measures to be integrated into the design or operation of a project, a variety of mitigation options are available to protect and enhance aquatic biodiversity.

Opportunities for mitigating adverse effects of a water resource development consist primarily of the installation of habitat modifications either in the reservoir or in the river downstream from the project. Upstream, habitat maintenance or improvement can be achieved through placement of artificial habitat structures (wooden cribs, artificial islands, or submerged artificial reefs) in the impoundment. Downstream, habitat for riverine species may be improved by installation of various types of flow diversion structures, placement of large substrate elements in the main channel, or placement of spawning substrates in the channel.

Establishment and maintenance of fish populations is frequently accomplished through artificial stocking of various species within the impoundment or in the downstream reach. Selection of species to be stocked in either area must be based on availability of stocks and compatibility of the species both with other stocked species and with native species.

Other measures to mitigate potential impacts of a water resources development may include maintenance of suitable spawning areas, particularly for fish populations. Construction of artificial spawning areas either in the mainstem of the affected river, or in artificial side-channels to the mainstem, can replace spawning areas inundated by the project impoundment or upstream areas where passage to the sites is blocked by the project structures.

To fully integrate consideration of aquatic biodiversity into planning for water resource development, i.e. mainstreaming of aquatic biodiversity, requires commitment from all organizations involved in development of a project and this commitment must be made early in the planning process.

A fundamental commitment must first be made by the financial institutions providing the funds for developing the project. Financial institutions must redefine the concept of an Aoptimum@ development to include protection of the environment as part of the project concept and developers, as a condition of a loan, must be required to incorporate environmental protection measures into the overall proposed project. In evaluating the feasibility of a project (i.e. benefit/cost ratio), financial institutions must be able to account for incorporation of environmental protection measures either as a non-monetory benefit or as a reduction in the monetary benefit margin of the project.

Developers, at the same time, must be committed to proposing a water resources development plan that is environmentally compatible. Generally, developers only do what is necessary to accomplish their primary objective. To effectively integrate environmental consideration into a water resources development, developers must recognize their responsibility for maintaining the quality of the environment at the site of the project.

Engineers and planners must also be committed to incorporating environmental protection measures into the project. Generally, engineering organizations respond to the directions given them by developers and financial institutions. However, engineers, even when such criteria are not set forth in their directions, can select and integrate environmental protection measures into a project without dramatically affecting the overall project design.

The prime responsibility for incorporating effective environmental protection measures into a water resources development, however, is placed on the environmental scientists. The quality and amount of information provided to the financial institution, the developer and the engineer by the environmental scientists must be accurate and provide sufficient information to select and design structural or operational measures that effectively protect aquatic resources. Environmental scientists must focus their enquiries to obtain appropriate information necessary for incorporating effective protection measures into project plans.

In conclusion, many opportunities to integrate measures to protect aquatic biodiversity into planning for a water resources development are available and are effective. The responsibility for integrating consideration of aquatic biodiversity into the mainstream of project planning and development lies with all participants in the planning process including the financial institutions, the developers, the engineers and the scientists.