### MEMORANDUM

October 1 7 , 200 8 Marla Smith, Work Assignment Manager Bob Lordo, Battelle Work Assignment Leader Chris Sroka, Battelle Statistician EPA Contract No. EP - C - 05 - 030, Work Assignment No. 3 - 13 : 316b: Laboratory Test Data Related to Entrainment This memorandum presents entrainment data from studies that assessed the performance of fine mesh screens in reducing impingement mortality and entrainment under controlled laboratory conditions. These entrainment data originated from documents which we have been reviewing on this work assignment and its predecessor in support of the Section 316(b) rulemaking effort. This memorandum also summarizes the results of statistical analyses to evaluate whether slot width and slot veloc ity

have a significant impact on the percentage of organisms that are entrained through the screens. Measure of Performance Considered in the Laboratory Studies Ideall y, we would use the laboratory study data to derive the same performance measure as that used in the field studies: percentage reduction in entrainment. Recall that this measure requires measurements from paired density samples taken in front of and behind a screened intake. However, none of the encountered laboratory studies performed this ty pe of sampling. Instead, the laboratory

studies measure d the extent of entrainment (and impingement mortality) associated with the installed screens within the test flume. Therefore, t he p ercentage of organisms that were entrained through the screen (i.e., percent entrainment) i s the performance measure used in the summaries and anal ys es of laboratory data in this memorandum
. Note that because field and laboratory studies are utilizing different entrainment performance measures, it is not possible to make direct comparisons in the values of the performance measures between field and laboratory

studies. Sources of Entrainment Data from Laboratory Studies The summarized entrainment data used in this evaluation are documented in Tables 1 through 3. Table 1 summarizes entrainment for all organisms (i.e., all life stages), while Table 2 considers entrainment data for eggs only, and Table 3 documents entrainment for larvae (non
- eggs) onl y. These data represent summaries calculated across species of the data presented within the source specified in the first column. The summaries are presented b y slot size and, when specified, slot velocity and screen orientation (parallel or perpendicular to water flow). The Study ID is assigned to the given data within Battelle’s performance evaluation database. (The data from EPRI[2003] currently

exist in separate Excel worksheets, as they were captured in electronic form from a PDF version of the study report.) Date To From SubjectOctober 17 , 2008

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### Table 1. Percent Entrainment of All Organism Types by Screen Orientation, Slot Size, and Slot Velocity, as Reported from

Controlled Laboratory Studies

Data Source Study ID # Species Screen

Orientation* Slot

Size (mm) Slot

Velocity (m/s) #

Entrained** #

Released Av g. %

Entrained** Av g. %

Retained

Appendix C of EPRI, 2003 2001 WW lab study 1 0 0.50 0.15 39.70 2 , 000 1.99

2001 WW lab study 1 0 0.50 0.30 249.50 1 , 900 13.13 2001 WW lab study 1 0 1.00 0.15 255.20 1 , 800 14.18 2001 WW lab study 1 0 1.00 0.30 357.60 1 , 800 19.87 2001 WW lab study 1 0 2.00 0.15 504.60 1 , 800 28.03 2001 WW lab study 1 90 0.50 0.15 2.20 1 , 800 0.12 2001 WW lab study 1 90 0.50 0.30 2.20 1 , 800 0.12 2001 WW lab study 1 90 1.00 0.30 304.10 1 , 050 28.96 2001 WW lab study 1 90 2.00 0.15 893.70 1 , 800 49.65 Appen dix D of EPRI, 2003 2002 WW lab study 4 NS 0.50 0.15 649.60 5 , 688 11.42

2002 WW lab study 5 NS 0.50 0.30 471.70 4 , 285 11.01 2002 WW lab study 3 NS 1.00 0.15 1477.40 2 , 525 58.51 2002 WW lab study 3 NS 1.00 0.30 1859.70 2 , 773 67.06 2002 WW lab study 1 NS 2.00 0.15 900.40 1 , 125 80.04 2002 WW lab study 2 NS 2.00 0.30 427.60 1 , 874 22.82 Table 2 - 4 of EPRI, 2008 116 1 90 0.50 NS 9.00 120 7.50 92.50 116 4 90 0.50 NS 57.89 1 , 250 4.63 95.37 116 5 90 0.50 NS 36.54 1 , 695 2.16 97.84 Table 1 of To mljanovich et al., 1978 248 5 90 0.50 NS 0.36 99.64 249 6 90 1.00 NS 19.97 80.03 250 9 90 1.30 NS 35.67 64.33 251 4 90 1.80 NS 20.20 79.80 252 4 90 2.50 NS 32.60 67.40 Page 401 of Hanson et al., 1977 253 1 NS 1.01 NS 16.00 100 16.00 * 0=parallel to flow; 90=perpendicular to flow. ** Adjusted for collection efficienc y (CE) for WW lab studies. NS = Not specifiedOctober 1 7 , 2008

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### Table 2. Percent Entrainment of Eggs by Screen Orientation, Slot Size, and Slot Velocity, as Rep orted from Controlled

Laboratory Studies

Data Source Study ID # Species Screen

Orientation Slot

Size (mm) Slot

Velocity (m/s) #

Entrained* #

Released Av g. %

Entrained*

Appendix C of EPRI, 2003 2001 WW lab study 1 0 0.50 0.15 0.00 900 0.00

2001 WW lab s tudy 1 0 0.50 0.30 0.00 900 0.00 2001 WW lab study 1 0 1.00 0.15 0.00 900 0.00 2001 WW lab study 1 0 1.00 0.30 0.00 900 0.00 2001 WW lab study 1 0 2.00 0.15 0.00 900 0.00 2001 WW lab study 1 90 0.50 0.15 0.00 900 0.00 2001 WW lab study 1 90 0.50 0.30 0.00 900 0.00 2001 WW lab study 1 90 1.00 0.30 0.00 600 0.00 2001 WW lab study 1 90 2.00 0.15 21.00 900 2.33 Appendix D of EPRI, 2003 2002 WW lab study 1 NS 0.50 0.15 0.00 1 , 122 0.00

2002 WW lab study 2 NS 0.50 0.30 100.20 1 , 737 5.77 2002 WW lab study 1 NS 2.00 0.30 407.60 1 , 125 36.23 * Adjusted for collection efficiency (CE) NS = Not specifiedOctober 1 7 , 2008

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### Table 3. Percent Entrainment of Larvae (non - eggs) by Screen Orientation, Slot Size, and Slot Velocity, as Reported from

Controlled Laboratory Stu dies

Data Source Study ID # Species Screen

Orientation* Slot

Size (mm) Slot

Velocity (m/s) #

Entrained** #

Released Av g, %

Entrained** Av g. %

Retained

Appendix C of EPRI, 2003 2001 WW lab study 1 0 0.50 0.15 39.70 1 , 100 3.61

2001 WW lab study 1 0 0.5 0 0.30 249.50 1 , 000 24.95 2001 WW lab study 1 0 1.00 0.15 255.20 900 28.36 2001 WW lab study 1 0 1.00 0.30 357.60 900 39.73 2001 WW lab study 1 0 2.00 0.15 504.60 900 56.07 2001 WW lab study 1 90 0.50 0.15 2.20 900 0.24 2001 WW lab stud y 1 90 0.50 0.30 2.20 900 0.24 2001 WW lab study 1 90 1.00 0.30 304.10 450 67.58 2001 WW lab study 1 90 2.00 0.15 872.70 900 96.97 Appendix D of EPRI, 2003 2002 WW lab study 4 NS 0.50 0.15 649.60 4 , 566 14.23

2002 WW lab study 3 NS 0.50 0.3 0 371.50 2 , 548 14.58 2002 WW lab study 3 NS 1.00 0.15 1477.40 2 , 525 58.51 2002 WW lab study 3 NS 1.00 0.30 1859.70 2 , 773 67.06 2002 WW lab study 1 NS 2.00 0.15 900.40 1 , 125 80.04 2002 WW lab study 1 NS 2.00 0.30 20.00 749 2.67 Table 2 - 4 of EPRI, 2008 116 1 90 0.50 NS 9.00 120 7.50 92.50 116 4 90 0.50 NS 57.89 1 , 250 4.63 95.37 116 5 90 0.50 NS 36.54 1 , 695 2.16 97.84 Table 1 of To mljanovich et al., 1978 248 5 90 0.50 NS 0.36 99.64 249 6 90 1.00 NS 19.97 80.03 250 9 90 1.30 NS 35.67 64.33 251 4 90 1.80 NS 20.20 79.80 252 4 90 2.50 NS 32.60 67.40 Page 401 of Hanson et al., 1977 253 1 NS 1.01 NS 16.00 100 16.00 * 0=parallel to flow; 90=perpendicular to flow. ** Adjusted for collection efficienc y (CE) for WW lab studies. NS = Not specifiedOctober 17 , 2008

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### The data in Tables 1 through 3 originate from the following four documents :

 EPRI(200 3 ) is a biological evaluation of cylindrical wedgewire screens performed at Alden Research Laboratory ’s Fish Testing Facility. Two distinct sets of tests were performed that involved releasing a specified number of larvae/eggs into a test flume
. One test was conducted in 2001, with striped bass larvae (length range: 3.5 to 10.6 mm; width range: 0.1 to 2.0 mm) and a surrogate egg ty pe (diameter range: 3.6 to 6.3 mm) , whose objective was to determine if the test facility and procedures could be used to evaluate effectiveness of the various screen types. After necessary modifications were made to the procedures based on 2001 testing, more comprehensive testing was done in 2002 that considered additional species that exist within a wide range of water body types and that represent a greater range of swimming capabilities. Eggs used in the 2002 study represented alewife (diameter range: 0.5 to 0.9 mm) and white sucker (diameter range: 2.8 to 3.5 mm) , while larvae represented bluegill, carp, rainbow smelt, winter flounder, white sucker, and yellow perch. Mean lengths of these larvae ranged from 6.1 mm (winter flounder) to 18.5 mm (bluegill), while mean widths ranged from 0.8 mm (yellow perch) to 5.4 mm (bluegill). Both of the 2001 and 2002 studies controlled for the following: o Slot size (0.5, 1.0, 2.0 mm) o Slot velocity

(0.15, 0.30 m/s) o Channel (or approach) velocity ( 0.08, 0.15 , 0.30 m/s ). (Not all species of larvae were tested at all slot size/velocity combinations in the 2002 study .) In addition, the 2001 study collected data for two different screen orientations: parallel (radial slots) and perpendicular (axial slots) to the water flow. In 2001, three test replicates were performed for each set of test conditions, while up to five replicates were performed in 2002 testing. The test flume channel in 2001 testing was 1.5 m wide, and water depth was 1.3 m. In 2002 testing, flume width and water depth were both 1.8 m. The 2001 and 2002 data are summarized separately. In both tests, entrainment data were reported after being adjusted for net collection efficiency (as determined from releasing known amounts of fish or eggs directl y into the entrainment collection tank).

 EPRI(200 8 ) is a two
- ye ar biological evaluation of fine mesh traveling screens whose main objective was to determine retention and post
- impingement survival of larval fish on the screens. These tests were performed in a closed
- loop testing facility at Alden Research Laboratory
. The test flumes were 30.5 cm wide and contained water 30.5 cm deep, and fine
- mesh screens were mounted perpendicular to the flow. Fish larvae were introduced to the s ys tem, then the s tudy evaluated the length of time at which the larva e could be impinged on the screen s before being rinsed off the screen s and b ypassed to holding tanks. The data presented in this memorandum originate from an investigation of the ability

of 0.5 mm mesh s creens to prevent the entrainment of larval fish that occurred within impingement survival testing in Phase I (in 2006). When using 0.5 mm mesh screens, survival testing involved performing four replicates for selected combination s of the following: o Lar val species (blue catfish, channel catfish, emerald shiner, fathead minnow, and smallmouth bass)October 1 7 , 2008

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### o Approach velocity (0.152, 0.35, and 0.61 m/s) o Duration of impingement on the screens (4, 8, 16 min.)
. The lengths of the larvae ranged from 6.9 to 23.4 mm (Ta ble 2
- 3 of EPRI, 2008).

 The study

in Tomljanovich et al. (1978) was performed in a fine
- mesh screening test flume (2.4 m wide x 1.2 m deep) at the Tennessee Valley Authority

(TVA) to evaluate the extent to which post
- impingement survival of fish larvae were related to impingement duration, fish species and size, approach water velocity, and screen mesh size. The study measured percent retainment of the larvae within various numbers of tests for selected combinations of the following: o Species (jewelfish ci chlid, threadfin shad, golden shiner/fathead minnow, white sucker, channel catfish, striped bass, bluegill, smallmouth bass, largemouth bass, walleye) o Mesh size (0.5, 1.0, 1.3, 1.8, 2.5 mm) of screens oriented perpendicular to flow. According to Table 1 o f Tomljanovich et al. (1978), a pproach velo cities ranged from 0.152 to 0.46 m/s among the tests , and test duration ranged from 0.5 to 16 minutes. Mean larval lengths ranged from 6.2 (striped bass) to 39.5 mm (threadfin shad), while mean widths ranged from 0.7 (striped bass) to 4.2 mm (threadfin shad). Exact numbers of fish in each test were unknown but ranged from 10 to over 200.

 The study

in Hanson et al. (1977) was performed in an oval test flume (0.84 m wide and 1.22 m deep) at the Delmarva Power and Light test laboratories. While this reference documents several phases of testing to evaluate entrainment and impingement of eggs and larvae b y a profile wire screen with 1 mm slot width , only a set of test s involving the introduction of 100 striped bas s larvae into the test flume appeared to measure entrainment through the screen, and therefore, was relevant for this memorandum. These tests were performed at an intake velocity ranging from 0.152 to 0.46 m/s, and duration of 30 minutes. Larval lengths ranged from 8 to 17 mm. Note that only

EPRI (2003) controlled for slot velocity in its tests; no other document reported slot velocity . Furthermore, EPRI(2008) and Tomljanovich et al. (197 8 ) reported “percent retention” data, rather than percent entrained data. EPRI (2008) also reported the number of organisms that were released in the test flume. As noted below, w e assumed that any fish not “retained” was entrained, and therefore, we calculated the numbers of organisms entrained as the number released minus the number retained. Hanson et al. (1977 ) did not report the number of organisms released, and therefore, we calculated percent entrainment as 100% minus perc ent retention for this study
. When numbers of entrained (or retained) organisms were reported in these references, they were summed across species and test replicates. Likewise, when numbers of organisms released into the test flume were reported, they were summed in the same manner. Both sets of sums appear in Tables 1 through 3
. Percent entrainment was then calculated as the total number of entrained organisms divided by

the total number released , and the tables include this result
. If a reference only reported percent entrainment, with no accompanying numbers of organisms entrained orOctober 1 7 , 2008

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### re leased, we calculated the average of these percentages across species and test replicates and presented them in Tables 1 through 3. Data Acceptance Criteria In order to be included in Tables 1 through 3 (and accepted for statistical analysis), entrainment data needed to achieve the following criteria:

 The data must originate from a study performed at a test laboratory under controlled conditions (e.g., not in a test barge placed in a natural water body).

 The test screens in this study must be categoriz ed as “fine mesh” screens, where the mesh size is clearly

specified.

 From the reported data, it must be possible to determine the percent of organisms that were entrained through the test screens.
o Data sources reporting only numbers of entrained fish w ere not accepted if the total number of fish released was not also reported.
o Data were not accepted if numbers of entrained organisms could not be determined with sufficient confidence from them. For example, if a data source reported a number or percentage of fish that avoided either impingement or entrainment and no other data, then these data were not accepted for use because it would not be possible to determine onl y those fish that were entrained from the reported data. While data were reported sp ecificall y on entrainment in EPRI(2008) and Hanson et al. (1977), the studies in EPRI(2003) and Tomljanovich et al. (197 8 ) measured “retainment” rather than entrainment. Organisms are “retained” when they do not pass through the intake screens, meaning that they

are either impinged on the screens, are able to keep swimming in front of the screens, etc. Thus, one may be able to assume that all organisms that are not retained are entrained through the screens. In order to accept data for studies that rep orted only retention data , it was necessary

to make this assumption. Therefore, when utilizing data from EPRI (2003) and Tomljanovich et al. (197 8 ) to characterize entrainment in this memorandum , this assumption should be noted. Plots of Percent Entrainm ent Data Figures 1 through 6 contain plots of the percent entrainment data, with Figures 1 and 2 presenting data for larvae, Figures 3 and 4 for eggs, and Figures 5 and 6 for all organisms. Odd
numbered figures plot the data versus screen slot width, with slot velocity noted by the plotting sy mbol. Even
-numbered figures include data only for EPRI (2003), with slot velocity specified along the horizontal axis and screen slot width given by the plotting s ymbol. The values plotted in these figures represent both parallel and perpendicular screen orientations (relative to flow).October 1 7 , 2008

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Figure 1. Percent of Larvae Entrained by Slot Velocity and Screen Size , with Screen Size on

the Horizontal Axis

Figure 2. Percent of Larvae Entrained by Slot Velocity and Screen Size , with Slot Velocity on

the Horizontal Axis 0 20 40 60 80 100 120

0 0.5 1 1.5 2 2.5 3 Screen Size (mm)Precent Entrainment of Larvae
Slot Velocity = 0.15 Slot Velocity = 0.3 No slot velocity given

0 20 40 60 80 100 120

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 Slot VelocityPercent Entrainment of Larvae

Screen Size = 0.5 Screen Size = 1.0 Screen Size = 2.0October 1 7 , 2008

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Figure 3. Percent of Eggs Entrained by Slot Velocity and Screen Size , with Screen Size on the

Horizontal Axis

Figure 4. Percent of Eggs Entrained by Slot Velocity and Screen Size , with Slot Velocity on

the Horizontal Axis 0 5 10 15 20 25 30 35 40

0 0.5 1 1.5 2 2.5 Screen Size (mm)Precent Entrainment of Eggs

Slot Velocity = 0.15 Slot Velocity = 0.3

0 5 10 15 20 25 30 35 40

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 Slot VelocityPercent Entrainment of Eggs

Screen Size = 0.5 Screen Size = 1.0 Screen Size = 2.0October 1 7 , 2008

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Figure 5. Percent of Total Organisms Entrained by Slot Velocity and Screen Size , with Screen

Size on the Horizontal Axis

Figure 6. P ercent of Total Organisms Entrained by Slot Velocity and Screen Size , with Slot

Velocity on the Horizontal Axis 0 10 20 30 40 50 60 70 80 90

0 0.5 1 1.5 2 2.5 3 Screen Size (mm)Percent Entrainment of Total Organisms

Slot Velocity = 0.15 Slot Velocity = 0.3 No slot velocity given

0 10 20 30 40 50 60 70 80 90

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 Slot VelocityPercent Entrainment of Total Organisms

Screen Size = 0.5 Screen Size = 1.0 Screen Size = 2.0October 1 7 , 2008

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### Note that because a large portion of the percent entrainment data values for eggs are zero (from the EPRI2001 study), Figures 3 and 4 appear to have fewer plotting points compared to the other plots. As noted in Table 2, no surrogate eggs were entrained in the EPRI 2001 study

except when the 2.0 mm screens were oriented perpendicular to flow. In addition, no entrainment of white sucker eggs o ccurred in the EPRI2002 study (although alewife eggs were entrained at high percentages). In both studies, the lack of entrainment was due to the large egg diameters related to the slot widths and the eggs’ “ability to maintain their shape and not be forced through the screens” (EPRI, 2003). These plots suggest that percent entrainment tends to increase with increased screen slot width for both egg and larval life stages. In contrast, increased slot velocity was more highl y associated with increased percent entrainment only for eggs. (This was observed primarily due to increased entrainment with alewife eggs at the 0.30 m/s slot velocity in the EPRI2002 study .) Conclusions on Slot Width and Slot Velocity as Noted by the Study Authors The following ty

pes of conclusions were made by the authors of the above studies upon review and anal ys is of the entrainment data. Onl y EPRI(2003) based some of its conclusions on entrainment or retainment data on the outcome of a statistical analys is (ANOVA). EPRI(20 03)

 Entrainment increased with increases in slot size and slot velocity
.  Entrainment decreased with increases in channel velocity
.  The ability

to characterize relationships in entrainment among the various test factors was hampered b y interactions among the factors or data gaps.  Most larvae and eggs were excluded from passing through 0.5 mm screens, but not larger mesh screens.  In the 2001 study, under the parallel screen orientation, entrainment rates increased significantl y with slot size (at the 0.05 level) and were higher at the 0.3 m/s slot velocity
.  In the 2002 study, s tatistical anal ys is was performed by species. S lot velocity

effects were significant at the 0.05 level on percent entrainment for larvae of selected species (e.g., winter flounder, yel low perch, carp). While it was not statistically significant, the anal ys is on winter flounder data indicated that the impact of slot velocity was greatest at the smallest screen mesh size. EPRI(2008)

 “The 0.5 mm screens used during survival testing were effective in retaining the majority of fish released.”  “In general, retention increased as (approach) velocity and duration of impingement increased.” Tomljanovich et al. (1978)

 “Velocity and test duration contributed little to percent retention.”  “Bo dy

length alone was not a good indicator of percent retention.”October 1 7 , 2008

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### In addition, EPRI(2003) cites Hanson et al. (1977) in making the following statement: “Impingement and entrainment have been positively correlated with slot velocity and inversel y related to ambient velocity .” Hanson et al. (1977) noted that over 90% of the tested larvae were able to swim for 30 minutes without entrainment when subject to currents of 1.0 to 1.5 fps. Statistical Analysis of Percent Entrainment Data in Tables 1 through 3 We utilized analysis of variance (ANOVA) methods to investigate the possible effect of screen size and slot velocity

on the percent of organisms entrained as reported in Tables 1 through 3 above. We applied ANOVA separatel y to each table (i.e., organisms in the egg life stage, organisms in the larval (non
- egg) life stage, and organisms in both life stages ) . We considered several ANOVA model forms that differed according to whether percent entrainment was transformed, whether slot velocity was included as a model predictor, and, if slot velocity was included, whether an interaction term between screen size and slot velocity should be included. Note that for eggs, percent entrainment was reported to be zero for most test conditions (Table 2), in part due to the limited number of laboratory studies that considered eggs, and to limited variation in the different ty pes of eggs that were considered in these studies (EPRI , 2003). Thus, conclusions from the statistical analyses performed only on eggs should be made with caution. Two-way ANOVA. S lot velocity data were available only for the 2001 and 2002 EPRI evaluation s of wedgewire screens (EPRI, 2003) . Thus, in the two
-way ANOVA model that included both slot size and slot velocity as predictor variable s, onl y data from EPRI(2003) were used to fit the model. The model that best fit the se data took the following form: Y ijk 

### =  + 

i 

### + β j 

### + ( αβ) ij 

### + 

ijk 

### (1) where Y

ijk 

### is the “inverse arcsine”
- transformed percent entrainment reported by the k th 

### study under the ith 

### slot width and jth 

### slot velocity conditions ,  is an overall constant,  i 

### is the amount contributed by

the ith 

### slot width ,  j 

### is the amount contributed by the jth 

### slot velocity, ( αβ) ij 

### is the amount contributed by

the combination of the ith 

### slot width and the jth 

### slot velocity, and  ijk 

### is random error left unexplained b y the model. Because only two values (0.15 m/s and 0.3 0 m/s) for slot velocity were represented among the available data , we considered the variable to be categorical like the slot width variable. The “inverse arcsine” transformation used in model (1), which EPRI (2003) also considered in its statistical analysis , is defined as follows : 

#   ijk ijk 

### X Y 1 

### sin  

###  

### , where X

ijk 

### is the percent entrained associated with the k th 

### study that utilized the ith 

### slot width and the jth 

### slot velocity
. We transformed the percent entrainment measure because plots of residuals from the ANOVA model fitting suggested that , for all three subsets of data, the errors were more likely to be independent and normally distributed with a constant variance upon taking thisOctober 1 7 , 2008

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### transformation
. We also considered a logarithmic transformation , which appeared to p erform similarly to the inverse arcsine transformation
. Upon fitting model (1) to data in Tables 1 through 3, we noted the following:  The interaction effect between screen size and slot velocity was significant for percent of larvae entrained (

p - value = 0.0134) and percent of eggs entrained ( p - value = 0.0198). Since there is an interaction effect, the effect of slot v elocity varies by screen size. For example, percent entrainment of larvae appears to increase at the lower slot velocity at 2.0 mm mesh s ize. The least squares estimates of the mean percent entrainment for each combination of screen size and slot velocity are shown in Table 4.  Only screen width was significant for percent of all organisms entrained ( p - value = 0.0263). The smallest screen width (0.5 mm) had the smallest percent entrainment, while the largest screen width had among the largest percent entrainment values
. Table 4 . Least Squares Means and 95% Confidence Limits for Percent Entrainment

Measured in EPRI (2003), by Screen Wid th and Slot Velocity, As Estimated from a Two -Way ANOVA M odel
Data Set Screen

Width (mm) Slot

Velocity (m/s) Least

Squares Me ans 95% Confidence

Limits for Least Squares Means Larvae Only 0.5 0.15 4.3% (0.6, 22.5)

0.5 0.30 10.0% (0.1, 32.4) 1.0 0.15 43.1% (12.9, 76.5) 1.0 0.30 58.3% (30.4, 83.6) 2.0 0.15 80.8% (54.7, 97.1) 2.0 0.30 2.7% (10.4, 37.4) Eggs Only 0.5 0.15 0.0% (0.0, 1.7)

0.5 0.30 0.7% (0.2, 4.4) 1.0 0.15 0.0% (0.0, 5.0) 1.0 0.30 0.0% (0.5, 2.5) 2.0 0.15 0.6% (0.7, 5.5) 2. 0 0.30 36.2% (16.6, 58.5) All Organisms 0.5 0.15 3.0% (2.0, 22.1)

0.5 0.30 6.0% (0.5, 28.6) 1.0 0.15 34.5% (5.7, 72.2) 1.0 0.30 37.9% (11.6, 68.9) 2.0 0.15 53.1% (23.0, 82.0) 2.0 0.30 22.8% (0.2, 74.8) 

### One-way ANOVA. Inorder to appl y more data from the above four documents into the ANOVA, we also fit a second model that included only screen mesh width as a predictor variable
. Thus, this model could assess onl y the effect of screen mesh width
. The form of this model is: Y jk 

### =  + 

i 

### +  jk 

### (2)October 1 7 , 2008

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### where the notation is the same as for model (1). We again investigated the residuals for this model and concluded that the assumptions of the ANOVA method were satisfied. Based on the results of the three runs of the model, we noted the following:  Screen width had a significant effect on average percent of larvae entrained ( p - value = 0.002) and the average percent of total organisms entrained ( p - value = 0.0109). This appears to be due to low percent entrainment outcomes associated with the 0 .5 mm mesh size. Greater percentages of entrainment were associated with larger mesh sizes.  Screen width alone did not have a significant effect on the average percent of eggs entrained. The least squares estimates of the mean effect of screen width are reported in Table 5.
Table 5 . Least Squares Means and 95% Confidence Limits for Percent Entrainment

Measured in Controlled Laboratory Studies, by Screen Width , As Estimated from a One-Way ANOVA model with Screen Width as a Factor
Data Set Screen

Widt h (mm) Least Squares Means 95% Confidence

Limits for Least Squares Means Larvae Only 0.5 5.2% (0.2, 16.3)

1.0 41.7% (21.4, 63.6) 1.3 35.7% (0.3, 88.6) 1.8 20.2% (1.4, 75.4) 2.0 59.2% (30.6, 84.8) 2.5 32.6% (0.0, 86.4) Eggs Only 0.5 0.2% (1.5, 4 .0)

1.0 0.0% (0.0, 5.2) 2.0 6.9% (0.1, 22.6) All Organisms 0.5 3.8% (0.4, 10.4)

1.0 30.7% (17.5, 46.1) 1.3 35.7% (4.9, 75.8) 1.8 20.2% (0.2, 59.6) 2.0 45.1% (25.4, 65.6) 2.5 32.6% (3.6, 73.0) 

### The outcome of the above statistical anal ys e s were compared to that observed with percent reduction in entrainment from field studies, as reported in Battelle’s technical memorandum dated September 29, 2008. The above anal ys is on laboratory data noted significant slot velocity effects (at the 0.05 level) separately for eggs and larvae (but not for all organisms) which varied according to the slot width size . However, as noted in the 9/29 memo, no significant slot velocity effects were observed in percent reduction in entrainment in field studies for any life stage, and the interaction of slot velocity and slot width was not significant
.October 1 7 , 2008

316b: Laboratory Test Data Related to Entrainment (EP
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### In both lab and field studies, increased entrainment was observed to occur with increased mesh sizes. However, the outcome of the statistical analyses (involving t he one
- way

ANOVA) differed between the two ty pes of studies. While screen mesh size was observed to have a significant effect on percent reduction in entrainment within the field studies for eggs only (and not for larvae or total organisms), mesh size was a significant factor for percent entrainment in the lab studies for larvae and total organisms (but not for eggs). For eggs, greater entrainment levels were observed in the field studies compared to the lab studies documented in EPRI(2003). Again, caution should be made when comparing data outcomes between the field and lab studies due to differences in how the performance measure was defined and in the ANOVA models applied to the performance measure data.
References EPRI(2008). Laboratory Evaluation of Fine

- Mesh Traveling W

ater Screens for Protecting Early Life Stages of Fish at Cooling W ater Intakes. Palo Alto, CA: Electric Power Research Institute, Inc. Technical Report No. 1014021. March 2008. EPRI(2003). Laboratory Evaluation of Wedgewire Screens for Protecting Early Life Stages of Fish at Cooling W

ater Intakes. Palo Alto, CA: Electric Power Research Institute, Inc. Technical Report No. 1005339. May 2003. Hanson, BN, Bason, WH, Beitz, BE, and Charles, KE. (1977). A practical intake screen which substantially

reduces the entrainment and impingement of early life stages of fish. In: Fourth National W

orkshop on Entrainment and Impingement . LD Jenson, ed. Melville, NY: EA Communications (a division of Ecological Analysts, Inc.) Tomljanovich, DA, Heuer, JH, and Voighlander, CW. (1978). Investigations on the protection of fish larvae at water intakes using fine
- mesh screening. In: Larval Exclusion Systems for Power Plant Cooling W

ater Intakes: Proceedings of the W orkshop Held at Shelter Island Inn, San Diego, CA , February 7

- 8, 1 978

. RK Sharma and JB Palmer, eds. Argonne, IL: Argonne National Laboratory
.