Technology Costing Modules Applied to Model Facilities

EPA developed the following costing modules for assessing model-facility
compliance costs for the Notice of Data Availability (NODA):

1.  Fish handling and return system (impingement only)

2.  Fine mesh traveling screens with fish handling and return
    (impingement & entrainment)

3.  New larger intake structure with fine mesh, handling and return
    (impingement & entrainment)

4.  Passive fine mesh screens at shoreline (impingement & entrainment)

5.  Fish barrier net (impingement only)

6.  Gunderboom (impingement & entrainment)

7.  Relocate intake to submerged offshore with passive fine mesh screen
    (impingement & entrainment)

8.  Velocity cap at inlet of offshore submerged (impingement only)

9.  Passive fine mesh screen at inlet of offshore submerged (impingement
    & entrainment)

10. Add/modify shoreline tech for submerged offshore (impingement only
    or I&E)

11. Add double-entry, single-exit with fine mesh and fish handling and
    return (impingement & entrainment)

The derivation and background for each of these technology modules is
presented in public record under the item titled, "316(b) Phase II NODA
Cost Modules."

For the main NODA option, each model facility had three potential
compliance actions: (1) no impingement and entrainment controls, (2)
impingement controls only, or (3) impingement controls plus entrainment
controls. A facility qualifies for compliance action (1) if it has
recirculating cooling systems in place. Figures 1 and 2 at the end of
this document provide a decision tree for assigning compliance actions
(2) and (3) to the in-scope Phase II model facilities. The following
files included in the public record present a roadmap of technology
upgrades for those facilities and intakes receiving compliance actions
(2) and (3):

-   316b_Phase2_DQ_MainOpt_Estuary.xls (compliance actions for estuarine
    and tidal river facilities responding to the detailed questionnaire)

-   316b_Phase2_DQ_MainOpt_FreshRiver.xls (compliance actions for
    freshwater river and stream facilities responding to the detailed
    questionnaire)

-   316b_Phase2_DQ_MainOpt_Lake_Ocean_GL.xls (compliance actions for
    freshwater lake and reservoir, Great Lake, and ocean facilities
    responding to the detailed questionnaire)

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-   316b_Phase2_STQ_MainOpt_Estuary.xls (compliance actions for
    estuarine and tidal river facilities responding to the
    short-technical questionnaire)

-   316b_Phase2_STQ_MainOpt\_ FreshRiver.xls (compliance actions for
    freshwater river and stream facilities responding to the
    short-technical questionnaire)

-   316b_Phase2_STQ_MainOpt_Estuary.xls (compliance actions for
    freshwater lake and reservoir, Great Lake, and ocean facilities
    responding to the short-tech. questionnaire)

Of the modules listed above, numbers 1, 5, 8, and in some cases 10 are
dedicated to impingement controls alone. The Agency generally applied
the remainder of the technology modules (including number 10 in some
instances) for cases where the model facility received entrainment and
impingement requirements.

In the cases that a facility had a functional impingement control system
at baseline and was deemed to require upgrades to entrainment controls,
the Agency generally assigned costs to the model facility to upgrade the
existing impingement controls in addition to the entrainment upgrade.
The Agency learned through its research subsequent to the February 2002
proposal that in most cases when upgrading a technology for entrainment
controls, the effort and cost of replacing the attached impingement
controls generally compared with the effort and cost to retain and reuse
the existing impingement controls (for more details, see the traveling
screen technology module documentation). The Agency assigned entrainment
only (with no additional impingement upgrade costs) requirements to a
few unique situations for the main option in the NODA. This included the
case of a low-velocity, double-entry, single-exit screening system
operating in-place at baseline. The Agency assigned only the costs
associated with adding fine-mesh overlays for this system because the
model facility had additional, redundant impingement technologies
in-place. In addition, those facilities with barrier net systems
in-place that required entrainment upgrades received only the
entrainment system costs, as the existing barrier net would be
functional regardless of changes to an intake structure.

The Agency based its approach of assigning costing modules to model
facilities on a combination of facility and intake-specific
questionnaire data in addition to satellite photos and overhead maps,
where available. Because not all facilities received the same
questionnaire, the Agency attempted to utilize data responses to
questions that were asked in both the short-technical and detailed
questionnaires whenever possible. In the end, the primary difference in
data analysis between short-technical and detailed questionnaire
respondents was the level to which the Agency developed costs. The
short-technical questionnaire responses did not provide significant
intake-level data, outside of intake identification information and
velocity. For instance, for the short-technical questionnaire, the
Agency did not obtain intake-specific information on the exact
technology in-place for each intake. The Agency instead obtained
technology in-place information at the facility-level for
short-technical questionnaires. Necessarily, the Agency utilized this
facility-level information for the short-technical respondents and
treated the facility as though it were a single intake with the
characteristics reported for the facility. For the detailed
questionnaire facilities, the Agency obtained sufficient intake-level
information to develop individual costing decisions for each intake.

The Agency utilized questionnaire data as the primary tool in the
assessment of the types of intake technologies applied at each
model-facility. For those facilities utilizing recirculating cooling
systems in-place, the Agency assigned no compliance actions as they met
the standards at baseline. For those with once-through, combination,
other, or unknown cooling system types, the Agency treated the facility
as though all intakes were of once-through configuration. The Agency
chose this method so as to conservatively estimate the compliance costs,
as the Agency's methodology utilizes flow as the independent variable.
The Agency then determined those intakes (facilities) that met
compliance requirements with technologies in-place. These facilities
received no capital or annual operating and maintenance compliance
upgrade costs (although they may receive administrative or monitoring
costs). The Agency then categorized facilities by questionnaire type
(that is, short-technical questionnaire and detailed questionnaire
respondents). Following the questionnaire division, the Agency
categorized facilities according to waterbody type from which they
withdraw cooling water. The Agency then sorted the intakes (facilities)
within each waterbody type based on their configuration as reported in
the questionnaires. (Note, as discussed above, the Agency examined
short-technical questionnaire facilities on the facility-level and
detailed questionnaire respondents by the intake level.)

Generally, the categories of intakes within one waterbody type are as
follows: canal/channel, bay/embayment/cove, shoreline, and offshore.
Once the intake (facility) is classified to this level the Agency
examines the type of technology in-place and compares that against the
compliance requirements of the particular intake (facility). For the
case of entrainment requirements, the only intake technology (outside of
recirculating cooling) that qualifies to meet the requirements at
baseline is a fine mesh screening system. Few intakes have fine mesh
in-place at baseline. Therefore, in the case of entrainment
requirements, most facilities with the requirement would receive
technology upgrades. The methodology for choosing these entrainment
technologies is explained further on in this discussion. For the case of
impingement requirements, there are a variety of intake technologies
that qualify to meet the requirements at baseline. The intake types
meeting impingement requirements at baseline include the following:
barrier net (the only fish diversion system which qualifies), passive
intakes (of a variety of types), and fish handling and return systems. A
significant number of intakes (facilities) have impingement technologies
in-place. Therefore, some intakes (facilities) require no technology
upgrades when only impingement requirements apply.

For facilities that do not pre-qualify for impingement and/or
entrainment technology in-place credits, the Agency focuses next on
questionnaire data relating to the intake type -- canal/channel, bay/
embayment/cove, shoreline, and offshore. Within each intake type, the
Agency further classifies according to certain specific characteristics.
For the case of bays, embayments, and coves, the Agency determined if
the intake is flush, protruding, or recessed from shoreline. For the
case of canals and channels, the Agency similarly focuses on whether the
intake is flush, protruding, or recessed from a shoreline. In addition,
the Agency calculates an approximate approach velocity using reported
information on the canal flow rate and cross-sectional area, where
applicable (specific to detailed questionnaire respondents only). The
approximated approach velocity aided the Agency in verifying the
reported mean intake velocity. For the case of shoreline intakes, the
Agency necessarily assessed whether the intake is flush, protruding, or
recessed. For the case of offshore intakes, the Agency examines whether
or not the intake has an onshore terminus (or well) and assesses the
characteristics of the onshore system.

The information the Agency gathers up to this point is sufficient to
narrow down the likely technology applications for each intake
(facility). However, in order to determine the best technology
application, the Agency also utilizes commercially available satellite
images and maps where available. The use of the satellite images and
maps aided the Agency in determining the potential for the construction
of expanded intakes in-front of existing intakes, the degree of
navigational traffic in the near vicinity of the intake, the potential
for an intake modification to protrude into the waterbody (such as a
near-shore t-screen) and whether a protrusion might be tolerated, the
possibility of installing a barrier net system, obvious signs of strong
currents, the relative distance of a potentially relocated intake inlet,
the possibility for fish return installations of moderate length,
etcetera. The Agency was able to collect satellite images for most
intakes (facilities) for which it required the resource. However, in
some cases (especially those in the rural, mid-western US), only maps
were available. Hence, for the case of a significant number facilities
located near small freshwater rivers/streams and lakes/reservoirs, the
Agency utilized only the questionnaire data and the overhead maps
available.

The Agency prepared a crosswalk and breakdown of the application of the
technology modules. The crosswalk provides specific factors that EPA
considered in the application of each module. The following sections
provide the factors that the Agency used in determining the proper
technology application and explain any exceptions to these cases.

*Module 1* - Add Fish Handling and Return System: This technology
applies almost exclusively for the case of impingement only upgrades.
The Agency applied this technology generally to facilities that when
requiring the impingement only upgrade had an existing traveling screen
system. The Agency applied this technology generally when the intake
velocity of the intake (facility) was roughly 1 ft/sec or below. The
rationale behind applying this technology in this case is that because
the intake velocity is relatively low and the existing traveling screen
system is functional, the fish handling and return system could be added
to the operating system and would perform under these conditions.
Vendors noted that approximately 75% of the existing screen components
would require replacement when adding fish handling and return. It would
be more prudent to replace the entire screen unit. (See Traveling Screen
cost module, page 5)

*Module 2* - Add Fine Mesh Travelling Screens with Fish Handling and
Return: This technology generally applies for the case of impingement
and entrainment upgrades. The Agency applied this technology to intakes
(facilities) with an existing traveling screen system in-place. The
Agency applied this technology when the intake velocity was roughly 1
ft/sec or below. The rationale behind the application is similar to that
of Module 1, in that the low existing velocity allowed for replacement
of the existing screen overlays without expanding the size of the intake
appreciably to lower the velocity. As a general approach, the Agency
applied this technology to a variety of waterbody types and intake
locations (such as in canals, in coves, and along shorelines). Note: in
addition to adding fine-mesh screens that this technology also replaces
the fish handling and return system of the intake. Note: this scenario
requires replacement of all screen units with units that include fish
handling and return features plus additional spray water pumps and a
fish return flume. Note: for those facility with existing screens and
fish handling and return and only entrainment reduction is required only
fine mesh screen overlay panels is applied.. See the documentation for
this particular module for more information.

*Module* 3 - Add New Larger Intake Structure with Fine Mesh, Handling
and Return: This technology generally applies for the case of
impingement and entrainment upgrades. However, in a few select cases,
the Agency applied it for the case of impingement only, more on that
below. The Agency applied this technology to intakes with a variety of
onshore configurations. The Agency applied this technology when the
intake velocity was above roughly 1 ft/sec. The rationale behind the
application is that demonstrated cases of operable fine-mesh screening
systems for large plants have used design velocities of roughly 1 ft/sec
or below. Because of the velocity implications, the Agency necessarily
required certain intakes (facilities) to enlarge their intakes.
Therefore, these intakes would be constructed anew in front of an
existing structure and tied in after construction complete. As a general
approach, the Agency applied this technology to a variety of waterbody
types and intake locations (such as in canals, in coves, and along
shorelines). Note that the Agency verified (through observation of
satellite images and overhead maps) that sufficient open water area in
front of the existing intake, and that the new protruding intake would
not hinder boat traffic. In a select few cases, the intake velocity of a
facility complying with the impingement only requirements was extremely
high. In these cases, the Agency may have applied this module to allow
for proper operation.

*Module 4* - Add Passive Fine Mesh Screens at Shoreline: This technology
applies mostly for the case of entrainment and impingement upgrades. The
Agency applied this technology generally in a very similar fashion to
Module 3 above. The primary difference for their applications is that
Module 4 is slightly more flexible in its location than Module 3 and
that Module 4 has the ability to be retrofitted to unusual intake
structures, such as protruding intakes, submerged shoreline intakes,
etc. In addition, the passive wedgewire t-screen system is very well
suited for application where currents are present, as the system is
designed to utilize currents for controlling impingement. The Agency
applied this technology generally when the intake velocity of the intake
(facility) was above roughly 1 ft/sec. However, that is not exclusively
the case, as there were exceptions where even for low velocity, unusual
passive screen systems, the Agency upgraded these intakes with Module 4.
This module, similarly to Module 3 above, would apply for a select few
cases that had extremely high intake velocities, even though they were
required to comply with impingement only.

*Module 5* - Add Fish Barrier Net: The Agency applied the barrier net
module to control impingement, both in the case of impingement only
upgrades and the combined impingement/entrainment upgrades. As a general
rule, the Agency applied the barrier net only to cases where it could
acertain that a favorable geographical condition existed, such as the
case of a wide mouth canal without boat traffic and low current
potential, the similar conditions in a wide mouth cove/bay, and the
similar conditions for a lake/reservoir shore. In a select number of
situations, the Agency applied both the fish barrier net system and an
entrainment controlling system. Generally, this was for the case that a
fish handling and return system could not reasonably be configured to
deliver impinged fish safely away from the intake. Therefore, the
barrier net served the purpose of preventing the cyclical
impingement/reimpingement condition in several cases. The Agency did not
examine velocities when applying barrier nets. Instead, the Agency
focused on the configuration of the intake and its adjoining shorelines.

*Module 6* - Gunderboom: The Agency did not apply this module for any of
the intakes/facilities for the Notice of Data Availability.

*Module 7* - Relocate Intake to Submerged Offshore with Passive Screen:
The Agency applied this costing module to address impingement and
entrainment requirements. The Agency applied this module, generally, to
any waterbody for which there was a clear advantage to its
implementation. What the Agency defined as an advantage for this module
generally related to the fact that an onshore or short canal intake
provided no clear avenue for applying one of the velocity reducing
modules, such as numbers 3 and 4. As a rule the Agency applied the
relocation of an intake to submerged offshore only for cases where the
existing intake velocity was significantly above 1 ft/s. Additionally,
the Agency relied on this module to represent situations where there was
not one module that stood out as the clear choice solution. Contrary to
intuition, the Agency learned in its research of offshore submerged
intakes that a good number are used in river environments. Hence, the
Agency utilized this module in several cases for large rivers. The
relocation distance utilized for each case was that derived from the
median of those within the intake\'s waterbody class.

*Module 8* - Add Velocity Cap at Offshore Inlet: The Agency applied a
velocity cap at the inlet of a submerged offshore pipe in several cases
to address impingement only requirements. The prerequisite for this
module was that the intake/facility had to have a submerged offshore
intake with no reported impingement controls. This combination was rare,
as most submerged offshore intakes had at least passive offshore intake
inlets. However, for the small number of cases where facilities did not
have impingement controls (or at least did not report them in the
questionnaire), the Agency applied this module to meet the impingement
only requirments. As a general rule, the Agency has reservations about
the ability of a velocity cap system to meet the numerical requirements
of the impingement standards. However, it should be noted that in the
case of offshore intakes that the \"location\" of an intake can be
considered for the compliance action. Therefore, an offshore intake with
a velocity cap is a combination that the Agency feels reasonably
represents the costs of complying with the impingement requirements.

*Module 9* - Add Passive Fine Mesh Screen at Inlet of Offshore
Submerged: The Agency applied a passive, fine-mesh, wedgewire, t-screen
system at the inlet of a submerged offshore pipe to address impingement
and entrainment requirements. The prerequisite for this module was that
the intake/facility had to have a submerged offshore intake with no
reported entrainment controls. In some cases, the intake (facility) may
have reported impingement controls, but the Agency generally ignored
these controls and presumed that the installation of the passive fine
mesh at the offshore inlet would suffice to control both entrainment and
impingement effectively. This module obviously is one of the simplest in
application, as it is clear for all intakes (facilities) through the
questionnaire whether or not their intake is submerged offshore. The
primary nuance for this situation exists where the intake (facility) may
have reported both offshore inlet controls and onshore screening
controls. See module 10 for more discussion of onshore screening
technologies for submerged offshore intakes. For the purposes of the
discusssion of this module, it should be noted that the Agency treated
the existance of an offshore inlet as the primary location for the
application of a compliance technology over an onshore modification
where both pre-existed.

*Module 10* - Add/Modify Shoreline Tech for Submerged Offshore: The
Agency did not apply this module for any of the intakes/facilities for
the Notice of Data Availability. Even though this technology would be a
reasonable method for an intake (facility) to comply with the rule, the
Agency chose not to use it. The basic reason that the Agency did not use
the technology was that in most cases where entrainment controls would
be required this method did not allow the reconfigured intake to be
enlarged in order to lower the intake velocity. In addition, the passive
screen intake at the inlet of the offshore pipe was more expensive, and
therefore, likely more applicable for a wider range of applications.

*Module 11* - Add Double-Entry, Single-Exit with Fine Mesh, Handling and
Return: The double-entry, single-exit screen provides a way for
facilities with limited ability to expand the size of their intakes to
lower the intake velocity (that is, increase the cross-sectional area of
the intake screens) without expanding the foot print of the intake. This
would be a useful application for facilities attempting to comply with
the impingement and entrainment requirements in the narrow terminus of a
canal or cove. Additionally, in cases where the intake is recessed from
shore, this technology can be applied to shoreline applications. The
Agency generally applied this technology when the intake velocity was
above roughly 1 ft/sec.

The Agency compiled a breakdown of the application of each module by
compliance requirement and waterbody type. These results are presented
in Tables 1 -- 3.

Table 1. Technology Module Applications for Facilities with Impingement
Requirements Only

  -------- ----------- ---------- ------- --------- -------------- ---------------
           Waterbody                                               
           Type                                                    

  Module   Lake/Res.   Great Lake Ocean   Estuary   River/Stream   All Waterbodies

  1        44          1          4       26        42             117

  2        0           0          0       1         3              4

  3        0           0          0       0         2              2

  4        0           0          0       1         6              7

  5        31          1          0       14        13             59

  6        0           0          0       0         0              0

  7        0           0          0       0         0              0

  8        8           0          0       1         0              9

  9        0           0          0       0         0              0

  10       0           0          0       0         0              0

  11       0           0          1       0         2              3
  -------- ----------- ---------- ------- --------- -------------- ---------------

Table 2. Module Applications for both Entrainment & Impingement
Requirements

  --------------------------------------------------------------------------------
           Waterbody                                               
           Type                                                    
  -------- ----------- ---------- ------- --------- -------------- ---------------
  Module   Lake/Res.   Great Lake Ocean   Estuary   River/Stream   All Waterbodies

  1        0           0          0       0         1              1

  2        0           13         2       23        34             72

  3        0           7          0       10        4              21

  4        0           5          1       13        42             61

  5 +      0           2          0       1         1              4

  6        0           0          0       0         0              0

  7        0           2          1       4         10             17

  8        0           0          0       0         0              0

  9        0           12         11      2         6              31

  10       0           0          0       0         0              0

  11       0           17         5       19        15             56
  --------------------------------------------------------------------------------

Note: Module "5+" represents the application of module 5 combined with
another module.

Table 3. Module Applications for All Requirements and All Waterbody
Types

  ------------------------ ----------------------------------------------
  Module                   All Waterbodies

  1                        118

  2                        76

  3                        23

  4                        68

  5                        63

  6                        0

  7                        17

  8                        9

  9                        31

  10                       0

  11                       59
  ------------------------ ----------------------------------------------

Examples of the Application of Technology Modules to Model Facilities

Because the determination of the best technology application depends on
a variety of factors and there is a large population of intakes to which
these multiple factors apply, the Agency views a series of examples as
the best means for demonstrating the logical progression that it applied
to the decisions. Based on the classification system described above,
the Agency presents examples of each major intake type -- canal/channel,
bay/ embayment/cove, shoreline, and offshore-- to aid the understanding
of the Agency's costing assignment process.

Example 1: Canal or Channel Intake

In this example, an intake withdraws cooling water through a canal
branching off a tidal river. The intake is a shoreline intake, flush
with the shore and built at the terminus of the canal. Based on its
characteristics, the facility is subject to impingement and entrainment
requirements. The Agency determined that the intake is at the terminus
of the canal by examining the satellite imagery and overhead maps, using
the reported latitude and longitude of the intake. The detailed
questionnaire reports that the existing intake is a coarse-mesh
traveling screen with a fish diversion system in-place. The Agency
determined that the reported fish diversion technology in-place was a
fish-bypass technology using the satellite imagery. The reported mean
intake velocity is 1.5 ft/s, and the Agency calculated the approximate
canal approach velocity as 1.4 ft/s based on the canal cross-sectional
area and flow rate reported in the questionnaire. Therefore, the Agency
concludes that the reported intake velocity is accurate. The canal
length is reported at 100 ft. Both the overhead map and satellite photo
demonstrate that the intake is close to this estimated length. In
addition, the Agency observes that the intake location at the terminus
of the canal is less than 100 feet from the bank of the tidal river. The
Agency determines that the mouth of the canal is not significantly wider
than the canal itself and that the apparent route of boat navigation is
to utilize a portion of the canal for barge docking and traffic.

Based on the above factors, the Agency determines that the best
technology for this model intake application is a double-entry,
single-exit traveling screen with fine-mesh overlay and a fish handling
and return system. The reason that the Agency utilized a double-entry,
single-exit system in this case is that the velocity of the intake is
significantly above 1 ft/s. The double-entry, single-exit systems
provide increased surface area (compared to a single-entry, single-exit
system) without significantly enlarging the horizontal footprint of the
intake. Therefore, for the case of a canal terminus, where enlarging an
intake's width cam be impractical, the double-entry, single-exit system
allows the intake velocity to be lowered to level that is in keeping
with current practice for fine-mesh, entrainment controlling systems.
The Agency studied existing cases of retrofit fine-mesh screen
applications and found the 1 ft/s threshold a reliable design criterion
for large intake systems where surface area can be constricted. The fish
handling and return system in this case addresses the impingement
control requirements. Because the canal is not long and the return
branch would be of reasonable length, the Agency considered the fish
handling and return system to be appropriate. The existing fish by-pass
system is not considered to be adequate (in and of itself) for meeting
the impingement requirements of the national rule. In addition, the
navigational use of the canal and the canal's limited throat width
necessarily prevents the use of a barrier net system.

In this case, the Agency determines that the debris loading potential
near the intake is high. This is due to the clear evidence of boat/barge
traffic and the known nature of the particular tidal river from which
this facility withdraws water.

Example 2: Bay/Embayment/Cove

In this example, an intake withdraws cooling water from a Great Lake.
The intake is a shoreline intake, flush with shore and built at the
terminus of the cove. Based on its characteristics, the facility is
subject to impingement and entrainment requirements. The Agency
determined that the intake is at the terminus of the cove by examining
the satellite imagery and overhead maps, using the reported latitude and
longitude of the intake. The detailed questionnaire reports that the
existing intake is a coarse-mesh traveling screen with no impingement
reducing technologies in-place. The reported mean intake velocity is 2.0
ft/s. Both the overhead map and satellite photo demonstrate that the
cove recedes approximately 500 ft from the main water body. The Agency
determines that the mouth of the cove is approximately 250 feet in
width. Based on the overhead map and satellite image, there is no
evidence of boat traffic in the cove. The railroad access and highway
access of the plant apparently meet the fuel delivery needs of the
plant.

Based on the above factors, the Agency determined that the best
technology for this model intake application is construction of a new,
larger intake directly in front of the existing structure. In addition,
the Agency determined that a barrier net system would address the
impingement requirements imposed on the intake. The reason that the
Agency utilized a new, larger intake system in this case is that the
velocity of the intake is significantly above 1 ft/s and the there is
ample room directly in front of the existing intake to allow for the
larger intake. Another alternative would be to use the double-entry,
single-exit screen as in the above canal example. The larger intake
system provides increased surface area (compared to the existing
single-entry, single-exit system), thereby reducing the intake velocity
to a level that would facilitate use of the fine-mesh system.

A fish handling and return system in this case would be difficult to
implement due to the orientation of the deep cove. The Agency would be
concerned about the creation of a cyclical impingement condition, which
would exacerbate the strain on the organisms. A 500-foot return system
could be built, but the alternative system of a barrier net is favorable
for this particular situation, in the Agency's view. The lack of
navigational use of the cove and the cove's wide throat provides a good
environment for barrier net deployment.

In this case, the Agency determines that the debris loading potential
near the intake is low. This is due to the lack of boat/barge traffic
evidence and the known nature of the particular Great Lake from which
this facility withdraws water.

Example 3: Shoreline

In this example, an intake withdraws cooling water from a freshwater
river. The facility withdraws more than 5 percent of the mean annual
flow of this river. Hence, it is subject to impingement and entrainment
requirements. The intake is a shoreline intake, protruding from shore.
The Agency determined that the intake extends 10 feet into the waterbody
by examining the satellite imagery and overhead maps, using the reported
latitude and longitude of the intake. The Agency also observes that the
apparent river width at the intake location is well over 100 feet. The
intake is located on a straight section of river, and an approximately
15 foot protruding diversion wall protects the intake from river debris
and traffic. The detailed questionnaire reports that the existing intake
is a coarse-mesh traveling screen with a fish handling and return
system. The reported mean intake velocity is 3.0 ft/s. Based on the
satellite images, there is evidence of coal barge traffic near the
intake, but significantly far away to allow for the protruding intake.

Based on the above factors, the Agency determines that the best
technology for this model intake application is construction of a
fine-mesh, cylindrical, wedge wire t-screen system. This passive intake
would be constructed to branch from the original protruding intake. In
the Agency's view, the wedge wire t-screen system will address the
impingement and entrainment requirements imposed on the intake. The
reason that the Agency utilized a new intake system in this case is that
the velocity of the intake is significantly above 1 ft/s and there is
already precedence to allow for a protruding intake. With the
construction of a properly sized replacement intake, the velocity can be
lowered for entrainment and impingement controls, and the current of the
river can be utilized to aid the operation of the intake. Another
alternative would be to use a new, larger intake protruding into the
waterbody as in the cove example above. Both of the larger intake system
provides increased surface area (compared to the existing single-entry,
single-exit system), thereby reducing the intake velocity to a level
that would facilitate use of the fine-mesh system. However, the
wedgewire screen system would provide additional advantages in the form
of inherent impingement controls. A fish handling and return system with
a traditional traveling system could be an option.

In this case, the Agency determines that the debris loading potential
near the intake is high. This is due to the clear evidence of boat/barge
traffic and the known nature of the particular river from which this
facility withdraws water.

Example 4: Offshore

In this example, an intake withdraws cooling water from a submerged
offshore intake in an Ocean. At the offshore inlet of the intake is a
velocity cap crib built approximately 500 feet from shore. The facility
is a short-technical questionnaire facility, and the Agency has no
information as to whether or not the intake delivers water to an onshore
well. Based on observations of the satellite imagery, the Agency was
also unable to identify an onshore well. Based on its characteristics,
the facility requires an entrainment technology upgrade. The existing
intake -- a velocity cap system -- is insufficient to meet the
entrainment requirements. The facility reports no other impingement or
entrainment technologies in-place. The reported mean intake velocity is
1.0 ft/s.

The Agency is unable to verify or disprove the length of the submerged
offshore intake with overhead maps and satellite photos, as it did for
the cases of canal and cove distances. However, the distance of the
intake offshore may not be relevant for certain costing modules.

Based on the above factors, the Agency determines that the best
technology for this model intake application is construction of a
fine-mesh, cylindrical, wedge wire t-screen system constructed at the
inlet of the offshore, submerged intake piping. The reason that the
Agency utilized an inlet t-screen system in this case is that, to the
best of its knowledge, the Agency determined there is no onshore
technology in use. Had an onshore technology been reported or observed
for the facility, the Agency could have considered upgrades to that
technology system (such as replacing coarse-mesh screen overlays with
fine-mesh, etc.). However, the Agency opted to utilize a technology that
would work for the description of the facility in its possession. With
the construction of a properly sized replacement intake, the velocity
can be maintained at a low level (1 ft/s) for entrainment and
impingement controls, and the natural currents of the Ocean can be
utilized to aid the operation of the intake.

In this case, the Agency determines that the debris loading potential
near the intake is high. This is due to the fact that this intake is in
a coastal Ocean setting.

**Figure 1.** Impingement Controls Flowchart for Model Facility
Compliance Costs

**Figure 2.** Entrainment Controls Flowchart for Model Facility
Compliance Costs

**Figure 2 (cont.).** Entrainment Controls Flowchart for Model Facility
Compliance Costs