| Option |
Type |
Drive
System |
Cleaning
System |
Typical
Application |
Advantages |
Disadvantages |
| 1 |
Drum |
Electrical |
Designed
to pass debris, self-cleaning, flow through. |
Off
channel |
Drum
screens are conventional, reliable, and proven fish protection
devises. Typically they have the lowest operation and maintenance
cost. Provides redundancy at multiple screen facilities and
are not solely dependent on bypass flow to remove debris. |
Possible
fish entrainment from side and bottom seal wear, over topping,
and/or impingement and carry over. Designed with very close
tolerances, narrow water surface elevation (WSE), operating
range (i.e. 65% -85%), and susceptible to power outages. |
| 2 |
Drum |
Paddle
Wheel |
Designed
to pass debris, self-cleaning, flow through. |
Off
channel |
Same
as # 1, plus not dependent on electrical power, paddle wheel
can be remote from screen through the use of hydraulics. |
Same
as # 1, plus slightly higher capital costs for paddle wheel
section, also dependent on diverted flow for powering cleaning
system. |
| 3 |
Drum |
Solar |
Designed
to pass debris, self-cleaning, flow through. |
Off
channel |
Same
as # 1, plus not dependent on electrical power. |
Same
as # 1, plus susceptible to theft of solar components, site
location limitations (sufficient sun light), and limited screen
size capacity. Limited screen size. |
| 4 |
Drum,
Modular |
Paddle
Wheel |
Designed
to pass debris, self-cleaning, flow through. |
Off
channel |
Designed
for 3-6 cfs. Same as # 2 plus lower overall costs, ease of installation,
all metal, shop fabrication, reusable, cost savings on multiple
units, designed for remote installations. |
Same
as # 1 and 2. |
| 5 |
Drum,
Modular |
Solar |
Designed
to pass debris, self-cleaning, flow through. |
Off
channel |
Same
as # 3, designed for sites with low or no head, and water quality
and water flow reliability issues. |
Same
as # 3, plus slightly higher capital costs for solar system
site location limitations, (sufficient sun light), and susceptible
to theft of solar components, limited screen size. |
| 6 |
Belt,
Travelling |
Electrical |
Sweeping
flow and flow through self -cleaning. |
Off
channel/
stream bank |
Lower
fabrication cost over drum, better hydraulics, accommodates
fluxes in flow, elimination of entrainment from over topping.
Can be designed to remove debris from diverted flow. New age
plastic screen materials aid with corrosion problems. |
Possible
fish entrainment from side and bottom seal wear, more dependent
on sweep and bypass flow to remove debris, and susceptible to
power outages and silt accumulations. |
| 7 |
Belt,
Travelling |
Paddle
Wheel |
Sweeping
flow and flow through self -cleaning. |
Off
channel |
Same
as # 5, plus useful in remote sites, and lower operation and
maintenance costs. |
Same
as # 4, plus dependent on diverted flow for powering cleaning
system. |
| 8 |
Belt,
Travelling |
Solar |
Sweeping
flow and flow through self -cleaning. |
Off
channel |
This
is an option to # 6 and # 7, useful in low head applications. |
Same
as # 7, plus susceptible to theft of solar components, site
locations limitations, (sufficient sun light), and limited screen
size. |
| 9 |
Plate,
Vertical |
Electrical |
Brush
/ sweeping flow, air / water burst. |
Off
channel/
stream bank |
Positive
fish protection/exclusion, lower capital costs, good facility
hydraulics, smaller foot print. |
Single
cleaning system, complicated, higher maintenance costs, does
not work well in high silt environment. |
| 10 |
Plate,
Vertical
(Submerged) |
Electrical |
Brush
/ sweeping flow, air / water burst. |
Off
channel/
stream bank |
Typically
used for year round and winter operation. |
Same
as # 9. |
| 11 |
Plate,
Inclined |
Electrical |
Brush
/ sweeping flow, air / water burst. |
Stream
bank/
off channel |
Positive
fish protection/exclusion, lower capital costs, good facility
hydraulics, smaller foot print. |
Same
as # 8, plus complications of in stream construction, potential
flood damage, maintenance work may require HPA, site specific.
|
| 12 |
Plate,
Modular |
Paddle
Wheel |
Rotary
brush / sweeping flow. |
Off
channel |
Designed
for 0.5 to 3 cfs. Instant screening, inexpensive, reusable,
adaptable to remote sites, positive fish protection/exclusion. |
Dependent
on bypass flow to pass debris, dependent on constant flow to
drive cleaning system, limited to diversions of 0.5 to 3.0 cfs. |
| 13 |
Plate,
Modular |
Solar |
Air
burst, sweeping flow. |
Stream
bank |
No
fish bypass, no moving parts, lower capital cost. |
In
stream construction, potential flood damage, maintenance work
may require HPA, site specific. Limited to 0.5 to 2 .0 cfs,
Susceptible to theft of solar components, and site location
limitations (sufficient sun light). |
| 14 |
Infiltration
Gallery |
Gravity |
Sweeping
flow. |
Stream
bed/
stream bank |
Elimination
of push-up dams, positive exclusion, and no moving parts. |
Typically
very site specific, very few applications in WA, experimental
technology, low rate of long term successful operation, and
will require exception from NOAA Fisheries in ESA areas. |
| 15 |
Coanda |
Gravity |
Sweeping
flow. |
In
stream |
Positive
exclusion, no moving parts. |
Typically
very site specific, very few applications in WA, in stream application
may require the addition of a fish passage structure. |
