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8 Columbia River Technical Element This chapter provides a review and assessment of Integration Project science and technology (S&T) under the Columbia River Technical Element. This technical element supports studies to improve understanding of the river environment, particularly as it relates to contaminant inputs, transport, and impacts on biological systems. The Columbia River is likely to be the main pathway for contaminant transfer to humans because local populations rely on the river to various degrees for recreation, irrigation and drinking water, and other sustenance. Thus, to the extent that contaminants are present or are likely to be introduced into the Columbia River, understanding their fate and transport in the river system is important for protecting present and future human populations. COLUMBIA RIVER HISTORY' The Columbia River drains an area of 259,000 square miles (39,000 square miles in Canada). It is the fifth largest river in the United States in terms of area and the third largest in terms of discharge. There are more than 400 dams in the watershed that provide more than 21 million kilowatts of electrical power generating capacity including 11 dams on the Columbia River, 7 of which are located upstream from the Hanford Site and four downstream (Figure 8.1~. Damming of the Columbia was initiated in 1938 with the completion of the Bonneville Dam and ended in 1973 with the completion of the Mica Dam in Canada. The Hanford Reach extends from the Priest Rapids Dam upstream of the Hanford Site to the head of Lake Wallula, which was created by the McNary Dam (Figure 8.2~. It is the last free-flowing stretch of the Columbia River, although discharge through the reach has been altered by upstream controls. The historical variation in river stage through the reach of up to 27 feet has been reduced to 9-10 feet by dam construction. The information in this section was taken from several reports and papers, including Rickard and Watson, 1985; Minshall, 1988; Rickard and Gray, 1995; Zorpette, 1996; Williams et al., 1998; the Center for Columbia River History [http://www.ccrh.org/river/history.htm]; and the Pacific Northwest National Laboratory [http://www.pnl.gov/env/surface-water_surveillance.htm]. 108

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Columbia River Technical Element 109 From a historical perspective, the environmental characteristics of Hanford Reach can be divided into three periods, all of which are related to differing land use activities. The first period is pre-dam construction (prior to 1930), the second occurs during Hanford Site operations (1944- 1980), and the third includes post-Hanford operations and river restoration (1980-present). If.' a n - . tR~ Dim = .~ ''~'! WA . _ 1 __ cR^.~'7 V`\ 0 ~~ -~* , ID Riv~.rm~le t~arla3r 1:~.~3~' `~' '. ~ r Fatima Ri~re~r USE CctJllmbia River 350 345 >,'~ - : sake ~ . ~ ~ BY of.. u.~srn~^ U~1"' - ~a s~ch~n~t~ 0 5 10 Mi~s Length Figure 8.1 Plan view of the Columbia River in the vicinity of the Hanford Site. Numbers denote miles above the river mouth. SOURCE: BHI, 1999, Figure E-5.

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110 Science and Technology for Environmental Cleanup During the pre-dam construction period, the area around the Hanford Site was occupied for at least 10,000 years by several Indian groups. The first Euro-American exploration in the area was by Lewis and Clark in 1805. Indian groups ceded their lands to the government at the Treaty Council of 1855, leading to the expansion of Euro-American settlements. By 1860, a ferry was operating across the Columbia River at White Bluffs, one of the first permanent settlements in the Hanford area on the east bank of the Columbia River. General population increases with the influx of gold miners at about that same time encouraged ranching development across the Columbia Plateau. Steamboats were also operating on the Columbia River up to White Bluffs. 400 300 200 - E 100 .Q `1~) 200 100 1 _ 1944 Bonneville Or 1971 to Present I: Open Channel Flow , , ,_ ,~ \~rs A Priest Rapids Hanford ~ ' Reach ~ McNary _f9~ 1959 John Day 1~953 The Dallas ~ Bonnev~l~ IT '56 Dam~nstruction 0 100 200 300 400 Miles Above Mouth of Rwer Figure 8.2 Top: Profile of the Columbia River channel bed in 1944. Boffom: Profile of the river channel at present. Dates on the figure indicate dam completion. NOTE: msl = mean sea level. SOURCE: BHI, 1999, Figure E-4.

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Columbia River Technical Element 111 Arid conditions in the region prevented the spread of dryland farming, and agriculture was limited until irrigation canals were constructed in the late 1 880s and further expanded in the early 1 900s. Railroad construction led to the founding of Pasco and Kennewick in the early 1880s, but difficult weather and soil conditions frustrated the development of the area through the early 1 930s. Irrigation projects bringing water to the north and east of the Hanford Site were completed in the 1 950s and continue to support agricultural activity to the present. Although few water quality data are available prior to 1930, the lack of development and limited use of the river suggest that water quality was good. The natural flow variability limited riparian vegetation and contributed to varied habitat conditions supporting more than 44 species of fish in the Hanford Reach. With initiation of construction on the Hanford Site, small settlements were relocated and site worker populations were as high as 50,000 in the ~ 940s. Water quality records for discharges to the Columbia River become available with the advent of operations at the site. Beginning in 1944, operating reactors released heated water, radionuclides, and corrosion-inhibiting chemicals directly to the river (see Chapter 2~. The work force of 50,000 generated domestic waste that was also discharged to the ground and river. Between 1951 and 1965, the operating reactors released a maximum of 24,000 megawatts of heat and 10,000-12,000 curies of radionuclides to the river each day. It is estimated that 1 10 million curies of radiation were released to the river between 1944 and 1971 (Rickard and Watson, 1985; see Chapter 2~. Most of the released radionuclides had short half-lives, and releases included activation products associated with natural elements present in the cooling waters. These discharges introduced short-lived radionuclides such as phosphorus-32 and zinc-65 into river biota. Longer-lived radionuclides, now buried in river sediment, include cobalt-60, strontium-90, cesium-137, uranium-238, and plutonium- 238, 239, and 240. In addition to releases from the Hanford Site, irrigation return water from agricultural activity to the east of the site entered the Columbia River (as both surface and groundwater) near Ringold and Richland. Between 1964 and 1971, the single-pass plutonium production reactors were phased out (see Table 2.1 ) and chemical and radionuclide releases to the Columbia River essentially ceased. The N-Reactor continued to release heat, but little radioactivity. It was shut down in 1987. In the restoration phase that followed the shutdown of all production reactors, environmental surveillance work has found that radionuclides in blots in the Hanford Reach are the same as in blots from upstream reference reaches of the Columbia River where no radiation was released. The major environmental concern for river ecosystems is

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112 Science and Technology for Environmental Cleanup the regulation of flow from upstream dams. The lack of high-stage variability has altered riparian vegetation, and the presence of artificial water-stage controls has led to destruction of spawning reads (Figure 8.3) and stranding of fish, because stage variations now occur over hours rather than days to weeks as in the past (Williams et al., 1998~. The major continuing concerns about water quality in the Hanford Reach include the addition of agricultural chemicals, discharge of effluents from upstream industrial development, and the continuing contribution of low levels of contaminants from the Hanford Site through groundwater discharges into the river. Figure 8.3 Photo of spawning reads in the Hanford reach in a slough immediately downstream of the 1 00-F Reactor area. Downstream is to the left. SOURCE: Zack Carter, Boeing Computer Services.

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Columbia River Technical Element SCOPE OF THE COLUMBIA RIVER TECHNICAL ELEMENT The Columbia River Technical Element comprises five S&T activities with 21 individual projects (Table 8.1~: 1. Detailed conceptual model. This activity includes three projects (CR-1 to CR-3) intended to develop a conceptual model that accounts for contaminant fate and transport in the river system. 2. Information management. This activity includes four projects (CR-4 to CR-7) intended to develop a system to gather, screen, and manage data for the river assessment and also to populate this system with available data and information from both the Department of Energy (DOE) and external sources. 3. Characterization. This activity includes four projects (CR-8 to CR-1 1 ) intended to identify habitats, species abundance, and distributions and to determine biological transfer functions2 for contaminants-species combinations of interest. 4. Groundwater-river interface study. This activity comprises six projects (CR-12 to CR-17) intended to develop and test conceptual and numerical models for groundwater and contaminant discharges to the Columbia River. 5. Fate and transport. This activity comprises four projects (CR- 18 to CR-21 ) intended to develop and test conceptual and numerical models for fate and transport of contaminants in the river system. 113 The schedule and budget for the Columbia River Technical Element are given in Table 8.1. Projects are planned to run from fiscal year 1999 through fiscal year 2004, and work was under way in four of the five activities during the committee's review. The total planned funding for this technical element is $8.17 million, but the Integration Project plans to obtain at least half of this funding from Hanford's core programs, and some of the future funding may be provided by external sources such as DOE Headquarters. 2A biological transfer function is a measure of the movement of a contaminant between food-chain levels in an ecosystem- for example, the transfer between microscopic algae growing on rock surfaces in the river and the aquatic insects that graze on those algae.

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114 Science and Technology for Environmental Cleanup TABLE 8.1 Summary of S&T Activities and Planned S&T Projects Under the Columbia River Technical Element S&T Activity SAT Project Objectives Project Hanford EMSP Projects Duration Funding Funding Planned (fiscal (thousand (thousand years) dollars) dollars) Detailed 3 Develop a detailed 1999-2002 225a b o conceptual conceptual model of model the river system that includes critical components and processes and identifies important links Information 4 Develop an information 2001-2002 325b 0 management management system to gather, screen, and manage data and information for river assessment and populate this system with available data and information Charactenzation 4 Identify habitats, 2000-2004 3,520a c 0 species abundance, and distributions and determine biological transfer functions for contaminant-species combinations of interest Groundwater- 6 Obtain an improved 1999-2004 2,000a ~ 0 river Interface understanding of, and study develop and test conceptual and numerical models for, contaminant discharge from groundwater to the Columbia River Fate and 4 Develop and test 1999-2004 2,100a 0 transport conceptual and numerical models for contaminant fate and transport in the river system NOTE: EMSP = Environmental Management Science Program aAdditional funding for this work is being provided through the System Assessment Capability (see Chapter 4). The funding shown in the table will be provided by the Characterization of Systems Project (see Chapter 3). The funding shown in the table will be provided by the River Monitoring Project (see Chapter 3). dThe Integration Project intends to seek funding from national S&T programs (e.g., from DOE Headquarters) for some of this wor c. SOURCE: DOE, 2000a, Figure 4-1, Table 5-1.

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Columbia River Technical Element 115 EVALUATION OF WORK PLANNED UNDER THE COLUMBIA RIVER TECHNICAL ELEMENT The committee's assessment of this technical element is based primarily on a review of the Integration Project Roadmap (DOE, 2000a) and planning documents (DOE, 1 999e; DOE, 2000g) provided by the Integration Project and secondarily on information received at committee meetings. The latter includes a demonstration of a numerical model of the groundwater-river interface, discussions with several Integration Project investigators, and (for one committee member) a tour of the Hanford Reach. The committee provides assessments below of each of the S&T activities shown in Table 8.1. Three of the assessments are structured using the five evaluation questions that were first introduced in Chapter 6. There was not enough information available to use these questions to structure the remaining two assessments, so the committee instead provides brief commentaries. Conceptual Model Development The S&T projects under this activity are focused on the development of a river conceptual model. This model will provide a quantitative description of the processes that occur in various components of the river system, including the riparian zone and associated blots along the river, aquatic biota, groundwater-river interface, river bottom and sediments, river water column, and users of river resources. The model for this element is termed "conceptual" because it is focused on identifying important processes and links among the various model components listed above, and it will connect processes in the Hanford Reach with important river controls both upstream and downstream of the site. Once the important processes are identified, a numerical model that can simulate these processes will be developed. The conceptual and numerical models are being developed in three modules: (1 ) the zone of groundwater-river interaction; (2) hydrodynamic, sediment, and contaminant transport in the river; and (3) biological transport. The Integration Project plans to use the model results for site and downstream risk and impact assessments. The model is designed to estimate concentrations for four classes of radionuclides and two chemicals. The System Assessment Capability (SAC) will be the primary user of this model (DOE, 2000g).

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116 Science and Technology for Environmental Cleanup Can the objectives of the planned work be achieved? The Columbia River conceptual model as described in the SAC documents (e.g., BHI, 1999) is intended to account for important contaminant transport processes in the Columbia River. The inclusion in this model of regional-scale river processes is, in the committee's view, essential to obtain useful impact assessments, because conditions in the river at the Hanford Site are controlled by upstream dam operations as well as water quality management activities in the watershed. Based on the committee's understanding, this conceptual model can probably support SAC Rev. 0 needs (see Chapter 4~. The conceptual model may have limited resolution, however, because it models the river as a series of segments, each characterized by a set of average model parameters. The sizes of these segments were unspecified in the materials reviewed by the committee. The general structure of the conceptual mode! appears to the committee to be robust and may support expansion as needed to meet other, possibly as-yet-undefined, objectives in the future. Does the planned work represent new science ? The approach being taken is best described as the application of current science and modeling techniques, rather than new science. Many components of the model have already been developed and/or applied to the Columbia River. On the other hand, there are not, to the committee's knowledge, many models that integrate the complex linkages among the major components (i.e., groundwater, river hydrodynamics, biological receptors) of large river systems. In the committee's opinion, this conceptual modeling effort at Hanford, if successful, is likely to contribute to the development of capabilities that can be applied to other large rivers. Can the planned work have an impact on cleanup decisions at the Hanford Site? Although the river is a critical and visible element of the cleanup program, the Hanford Reach has already shown marked recovery from past contaminant discharges (see Chapter 2 and the discussion elsewhere in the chapter) because of its high capacity for dilution and transport. The committee expects that this conceptual model will confirm the Columbia River's capacity for self-maintenance and may support the prioritization of resources to those areas of the Hanford Reach subject to greatest contaminant loadings- for example, spatially restricted zones of contaminated groundwater discharge to the river bed. However, the present level of resolution of the model will likely be inadequate to support

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Columbia Giver Technical Element il 117 mpact assessments or decision making in these spatially restricted zones. Does the planned work acldress the important issues? The planned work is designed to develop a conceptual model that will support site decision making. The model may assist in impact analysis and contribute to more effective management of contaminants at the Hanford Site. As noted above however, the level of resolution in the model will limit its utility in addressing site-specific contaminant issues in the Columbia River. Are there other concerns, comments, or suggestions that should be considered by the Integration Project in executing the planned work? The committee has two general concerns about this S&T activity: the first is model resolution or scale, and the second is model validation. The concern related to model resolution involves the range of scales over which the model must operate. This issue of scale is addressed, in part, in discussions provided elsewhere in this report (see, for example, Chapter 6 and Appendix C). As noted previously, the plan to model the river as a series of segments, the lengths of which were undocumented in the materials reviewed by the committee, probably will preclude the use of this model to assess impacts from specific contaminant discharge zones in the bed of the Columbia River. The concern about model validation is also related to scale. Temporal and spatial mode! scales may range over 13 orders of magnitude. The selection of a single or even a limited number of scales for model analysis will affect model validation efforts. For example, the scale of the data to be used in model calibration and validation may not exactly match the scale of resolution of the model itself, particularly when historic data, which were not collected specifically to meet model needs, are used. Further, the inherent variability of large river ecosystems will complicate normal model validation efforts. Although the concerns about scale and validation raised here are relevant for any model development and application effort, the time scales associated with contaminant effect and the spatial scales associated with contaminant movement and effect suggest that these issues will be of particular importance to Columbia River modeling.

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118 Science and Technology for Environmental Cleanup Information Management Environmental data have been collected at the Hanford Site since it became operational in 1944. Additional monitoring programs have been put into place in succeeding decades in response to regulatory requirements, and these continue to generate large amounts of data. Recognizing the extent and complexity of existing data resources, the objective of the four S&T projects (CRY to CR-7) under this activity is to develop an information management system to "screen, manage, and disperse" data and information from both inside and outside Hanford. The information management system will be cleveloped by September 2001 and will be updated regularly as additional site data are collected. The committee recognizes the need for efficient and effective data management at the Hanford Site. There may be S&T needs associated with the development and application of new information technologies, but these were not made clear in the documentation reviewed by the committee. Therefore, given the apparent lack of an S&T context for this work, information management development would seem to be better handled in programs other than the Integration Project S&T program. With completion of the planned information management system later this year, additional S&T work does not appear to be needed on this issue. Characterization The four characterization projects (CR-8 to CR-1 1 ) under this activity involve fate and transport model parameterization and environmental data collection to support fate and transport analysis for future SAC revisions (see Chapter 4~. The projects under this activity will elucidate the transfer of contaminants through organisms and the identification of critical habitats. Because SAC revisions will require increasingly complex and detailed data, the characterization projects must meet future as well as present SAC data needs. Although details of future SAC revisions are not available at this time, the committee expects that model revisions will involve reductions in model scales (both spatial and temporal) to obtain increases in mode! resolution. The improved resolution may allow the models to be used to assess impacts at more spatially restricted river scales than is possible with the current generation of models. In general, the planned projects appear to the committee, at least on the surface, to be designed to respond to expected data needs. However, the available project descriptions are inadequate to allow detailed evaluations of individual projects. It is critical that these projects

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Columbia River Technical Element 119 be integrated effectively with those from the other technical elements to ensure that the data collected meet the "characterization" needs of those projects or provide sufficient information to support model calibration and validation. In the committee's view, an important S&T need under the characterization activity is to define and quantify impact"thresholds," that is, points at which small changes in environmental conditions can result in major changes to species habitat, abundance, or health. Similarly, the committee believes that the characterization activity should provide the Integration Project with techniques or characterization protocols that could support the development of new tools for impact assessment. The committee did not see this outcome explicitly identified, but documentation did suggest that improved impact assessment would be an outcome of this activity. Considering the scope of future management needs in the Hanford Reach, and the lack of full understanding of ecosystem structure and function in large river systems, the committee believes that new monitoring tools and techniques may be required to obtain the needed characterization data. The development of new large river and ecosystem monitoring tools" specifically to provide information about organism distribution and ecology in the river channel and the interaction between the river and the riparian zone is viewed by the committee as an important S&T gap in the current program. Although there are numerous biological monitoring tools available (Schaeffer and Herricks, 1993), these tools have limited application to ecosystem dynamics (Schaeffer et al., 1988~. This is particularly true for large river systems, the theoretical ecological foundations for which are based on research in small streams. Similarly, the interactions between rivers and riparian/floodplain ecosystems is an important element of river ecology (Ward, 1989) that is poorly understood for large rivers. It should be recognized that ecology is entering a new era of analysis supported by advancing technology (Thompson et al., 2001), which will allow researchers to address how biological and physical processes interact over multiple spatial and temporal scales. The committee believes that the S&T program should be oriented to advancing the capability for impact assessment in the Columbia River using the most modern monitoring and analysis tools available. The committee therefore recommends that the S&T program support the development of advanced biological monitoring approaches for the Columbia River. Additional details on this recommendation are provided in the last section of this chapter.

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120 Science and Technology for Environmental Cleanup Groundwater-River Interface The groundwater/river interface activity includes six projects (CR- 12 to CR-17) that are designed to model the interactions between groundwater and the Columbia River. The projects are focused on developing models and filling data needs by conducting field and complementary laboratory experiments. The planned investigations include the elucidation of dynamics of flow direction; contaminant attenuation, decay, and transformation; biological processes; transport rates; and preferential pathways associated with contaminant discharge from aquifers to the Columbia River. The models developed in these projects will provide the primary support for contaminant fate and transport analysis and eventual prediction of impacts. Planned activities include numerical model development and simulations to develop impact predictions. Based on DOE (20009), it appears that the first model development will be completed in fiscal year 2002. Can the objectives of the planned work be achieved? The groundwater-river interface activity is designed to support fate and effects analyses for the Columbia River. Although the documentation suggests a 2002 start date for this activity, as noted above, a model that integrates groundwater flow with river stage changes was demonstrated to the committee during one of its meetings, which suggests that progress already is being made on this activity. Some of the objectives of the planned work in project CR-13 depend on the completion of several field and laboratory investigations that have not yet begun. Planning documents reviewed by the committee suggest that these investigations are planned to be completed in approximately six months. This schedule is overly optimistic given the complexity of the planned work. Further, the projects that are supposed to compare predictive and observational data against impact criteria (CR-15 to CR-17) do not have clear plans or objectives. Without clearly defined objectives, it is not possible to evaluate project merit or to predict success. Does the planned work represent new science? The numerical model to be developed for the groundwater-river interface is unusual because of the river size and the rapid flow alterations due to upstream dam releases, which produces rapid changes in river stage, changes in hydrostatic regimes in the river banks, and corresponding changes in groundwater movement. This model will be able to build on the groundwater and vadose-zone modeling under way at

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Columbia River Technical Element the Hanford Site in that these models will provide good estimates of the rate of delivery and expected concentration of contaminants to the river bank area. This work has the potential to produce new insights, and the modeling approaches developed are potentially applicable to other large rivers. Can the planned work have an impact on cleanup decisions at the Hanford Site? 121 This model may allow the Integration Project to describe more effectively the interactions between groundwater and the Columbia River, which can contribute to understanding contaminant impacts on the river system. This model could lead to improvements in prioritization of cleanup activities based on future hazards to the Columbia River, if the model resolution issues raised previously are addressed. Does the planned work address the important issues? Given the fact that groundwater discharges along the Hanford Reach are on the order of 104-102 cubic feet per second and the average river discharge through the reach is on the order of 105 cubic feet per second, it is unlikely that groundwater discharges will substantially affect the Columbia River at the scale of the Hanford Reach this is true even for low-flow conditions, because river discharge is maintained by releases from upstream dams. This said, however, it is likely that groundwater contamination will enter the Columbia River in the future in spatially limited areas, as is observed today, creating locally high concentrations in or near habitats of important organisms (e.g., salmon) in the river ecosystem. Contaminant concentrations that affect river organisms at spatially restricted scales may not produce significant impacts on the Columbia River ecosystem as a whole. Nevertheless, it will be important to identify groundwater inflow locations to assess whether any effects on critical species or habitats should to be minimized. The proposed modeling activity could contribute to the identification of both critical habitats and species that may be affected by groundwater-related contaminants entering the river in the future. Fate and Transport The fate and transport activity comprises four projects (CR-18 to CR-21 ) that involve the development of a quantitative model for hydrologic, sediment, and contaminant transport. The activity will also

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122 Science and Technology for Environmental Cleanup include laboratory-based testing that will be concluded in 2002. Descriptions of these projects provided in DOE (2000g) suggest a focus on tracking contaminant transport for only a limited list of contaminants (described as nutrient and nonnutrient metals) in a limited selection of species (one fish and one aquatic invertebrate species). The contaminants and species to be studied will be identified during the projects. Can the objectives of the planned work be achieved ? Hydrologic models have been developed already by several organizations, and these models are being modified for application to the Columbia River. Therefore, the committee believes it is likely that the hydrologic modeling objectives of these projects will be achieved. The fate and transport activity also includes modeling of sediment and biological transport, as well as general contaminant transport in the Columbia River. The entire set of models will be evaluated against measurements and monitoring data from the Columbia River. The committee believes that it is likely that models that capture general process characteristics can be developed to meet the objectives of this activity. The committee believes it unlikely, however, that models incorporating even a moderate level of complexity can be developed in the time frame proposed. Does the planned work address the important issues? Contaminant transport through the Columbia River system is an important issue, which must be addressed through both modeling and data collection. An important use of models is to identify the critical data needed for site decisions. The committee believes that this modeling exercise, if executed well, could benefit existing river monitoring programs by contributing to a better review of data utility. This modeling exercise could also contribute to a better understanding of the possible implications of small-scale, or localized, contamination for broader ecosystem conditions in the river, if the models have the appropriate spatial and temporal scales. For example, if this modeling identifies transport pathways for contaminants or the propagation of effects from localized contaminant zones in the river, then the planned work may provide critically needed information to guide future research and data collection. The committee believes that these types of simulation models are best used to guide research and are much less useful for prediction of impacts.

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Columbia River Technical Element Are there other concerns, comments, or suggestions that should be considered by the Integration Project in executing the planned work? 123 The major concern associated with the fate and transport of contaminants from the Hanford Site is the potential for contaminants to produce harm for thousands of years. In predicting fate and transport, the models must account for long-lived contaminants. Further, the models must consider the effect of extremely rare events, such as catastrophic floods, on fate and transport. Comments on these issues are provided in Chapter 4; see also Chapter 9. SUMMARY AND DISCUSSION The committee believes that the S&T activities planned for the Columbia River Technical Element have the potential to contribute to a better understanding of the Columbia River, the interactions between groundwater flows from the Hanford Site and the river, and the potential effects of contamination from the Hanford Site on the river ecosystem. However, in many cases the documentation was insufficient to allow the committee to judge whether this potential is likely to be realized. The committee believes that the activities in the Columbia River Technical Element should be viewed in the broader context of the Columbia River watershed and the Hanford Reach. As noted at the beginning of this chapter, the Hanford Reach (Figure 8.2) is the last free- flowing stretch of the Columbia River. As the last remnant of a once-vast and important resource, the Hanford Reach certainly deserves attention from the Hanford Site's cleanup program although it may well be that the impacts of site contaminants on the reach are insignificant, and therefore the river may not be the most important factor in site cleanup - c eclslons. The Columbia River has undergone many changes over the last 100 years. It has been dammed, its flow has been altered, and its major fishery has been compromised. At the same time, the Columbia River has been subject to high thermal, raclionuclide, and other contaminant loads from the Hanford Site, with little apparent residual effects (e.g., PNNL, 1999; see also the discussion of Columbia River history elsewhere in this chapter). The Hanford Reach has been flushed by large volumes of water in the decades following the cessation of plutonium production operations at the site, and the Columbia River ecosystem has recovered through natural processes. Today, the Hanford Reach is one of the most valued and ecologically important stretches of the Columbia River. In light of the importance of the Columbia River, the committee recognizes the need for an integrated site and river model but cautions

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124 Science and Technology for Environmental Cleanup against overdependence on modeling, where scale and validation issues can compromise model utility. The committee sees a clear need for information management, but recognizes that information management will operate in support of other cleanup activities, rather than leading them. Similarly, characterization activities, the groundwater-river interface analysis, and fate and transport modeling are viewed by the committee as supporting, rather than leading, activities of the Integration Project. The committee has identified aclditional S&T needs in the Columbia River Technical Element. In particular, the committee finds a need for advanced modeling that will integrate results over the scales of analysis and the biological effects present in the Hanford Reach- Columbia River watershed. The committee supports better characterization of the environmental setting and better fate and transport information for contaminants and ecosystems. The committee recognizes, however, that limited resources may well be allocated to characterization of, or modeling contaminant transport from, areas of contaminant concentration such as the 200 Area. In other words, the committee would not place a priority in the S&T program for work in the Columbia River Technical Element given S&T needs of other technical elements. As noted elsewhere in this chapter, the committee recommends that the S&T program support the development of advanced biological monitoring approaches for the Columbia River. The committee believes that there is a critical need to develop new technologies for ecosystem assessment that will complement and expand the current radionuclide and chemical monitoring capabilities. There is an extensive literature on biological monitoring that provides a clear indication of the value of using blots as sensitive indicators, for example, of water quality (Rosenberg and Resh, 1993; Kerans and Karr, 1994~. Advanced biological monitoring procedures, which include a wide range of genetic, biochemical, organism, community, and ecosystem metrics, some measured in real time, represent the state of the art in assessing ecosystem quality and condition. Finally, the committee suggests that protection of the Columbia River may benefit from a monitoring program directed to the zones of effect in the groundwater-river interface. Biological monitoring of these areas will give more power to detect contaminant impacts on the biota relative to reach-scale assessments. Early determination of impact, or a finding of no impact, in the Columbia River would provide critical information for cleanup decisions at the Hanford Site.