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Flap Gatehttp://www.itrc.org/reports/FlapGate/FlapGate.pdf ITRC Report No. R 07-001
EMERGING TECHNOLOGIES
Flap Gate In 1992, the Irrigation Training
and Research Center (ITRC) atCalifornia Polytechnic StateUniversity began to investigate earlydesigns of Flap Gates. Originatingin Holland in the 1940s, the FlapGate is a simple, inexpensivehydraulic gate for automaticupstream water level control. Aftermodifications to the design weremade, ITRC and Chowchilla WaterDistrict constructed and tested Flap
Gate prototypes. Currently, there areover 60 ITRC Flap Gates in usewithin four districts. An Alta IDexample is shown below.
Flap Gate at Alta ID (7/24/00)
Benefits
The ITRC Flap Gate: Operates steadily at varying flowconditions
Maintains water level elevationtypically within 0.5 inches ofdesign, allowing maximum flowthrough the canal with littledeviation
Maintains consistency in watertravel times
Contains fewer mechanical partsthan most other gates Can be completed in one weekfrom design to installation withexperience
Is often installed in less than twohours and while water is flowing
Water delivery flexibility isenhanced because canals becomeeasier to operate
Design
A Microsoft Excel
spreadsheet atwww.itrc.org/reports/flapgate/flapgate.htmallows a user to customize a designof the Flap Gate for a given set ofdimensions of the location where thegate is to be in service. Practicalhints for successful application aswell as the theory behind the FlapGate are described in an
Irrigation Training and Research Center (ITRC) - www.itrc.org
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Flap Gatehttp://www.itrc.org/reports/FlapGate/FlapGate.pdf ITRC Report no. R 07-001
accompanying web site report, FlapGate for Automatic Upstream Canal
Control. The gate is easily constructed andbasically consists of steel, two bearings, twostruts, and few bolts and nuts, as well asmaterial for the counterweight.
InstallationThe ITRC Flap Gate is typically constructed
in the irrigation district shop. It is then installedusing a crane, which hoists the gate into place(depending on size) where it is secured withlarge bolts into a concrete structure. In mostcases, the gate may be placed where flashboardswere once located. Flap Gates are ofteninstalled in less than two hours and while wateris flowing.
After securing the gate, the counterweight ispartially filled with concrete. For smaller FlapGates, it may be possible to install the gate withsome of the counterweight material already inplace. In order to achieve the desired upstreamwater elevation, the Flap Gate is calibrated byadding lead buckshot or additional concrete tothe counterweight, which is located on the topof the Flap Gate as shown in the TurlockIrrigation District Flap Gate photo.
Flap Gate at Turlock ID (6/21/00)
MaintenanceThe Flap Gate is designed for automatic
function and requires virtually no maintenance,making the Flap Gate a very desirable choice forupstream control. It may be necessary to flushdebris such as twigs or other material from theFlap Gate every one or two days, but the Flap
Gate results in lower labor costs compared toflashboards because there are no boards to bechanged. The bearings, which allow the FlapGate to rotate, should be greased every year and
re-painting should be done when requireddependingupon use and climate conditions.
Water Conservation and Efficiency Improved control of farm deliveries enables
growers to effectively use their water Advanced control of water levels and ease of
operation reduces spills which reducespumping at the supply points of canals
CostCosts vary widely between districts. The
Turlock ID gates are generally the largest andhave been put into new structures costingup to $7000 for gates of about 120 CFS.Chowchilla Water District installs gates atabout 50 cfs for close to $1,600, includingfabrication and labor. Broadview WaterDistrict put in a 30 cfs Flap Gate forapproximately $700. Alta Irrigation
Districts gates cost about $1,100 to buildand install.
UseDistricts where the ITRC Flap Gate has beeninstalled (1/2001) include:
Chowchilla Water District- Currently 45 gates have been installed
with many more planned for the future. Turlock Irrigation District
- Currently four gates exist in the district.More are being planned to operate in the2001 irrigation season.
Alta Irrigation District- Ten gates are in use, and 50 more are in
the planning process. Broadview Water District- One gate is in use and district personnel
are reviewing potential locations.
Irrigation Training and Research Center (ITRC) - www.itrc.org
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Flap Gatehttp://www.itrc.org/reports/FlapGate/FlapGate.pdf ITRC Report No. R 07-001
ResultsEvery district surveyed reported that thegrowers who were affected by theinstallation of the gates were extremelypleased since the gate not only providedhigher water levels, but also allowedgreater flexibility in the ordering of water.
By installing the ITRC Flap Gate, adistrict will be able to better serve itscustomers. Growers and district staff invarious areas have frequently commentedon the consistent water levels provided bythe Flap Gate and encourage its usewherever possible.
Doug Welch, manager of Chowchilla WaterDistrict, has been instrumental in assisting with
the design and adoption of the Flap Gatetechnology.
The Flap Gate generally saves laborcost and mileage; ditchtenders do not haveto go back and forth along the canals asfrequently as with flashboards. Weed andpest control expenses are reduced due tohigher water levels. Plus, there may be anopportunity to have less spillage at the endof the system. Chowchilla Water District
saves on general maintenance, and haseliminated canal breaks where the gates areinstalled. The following breakdownillustrates which areas of operation havereduced in cost in Chowchilla WaterDistrict.
Chowchilla Water District Savings
Labor 8-10% Mileage 15% Weed Control 2-3%
For Further Information
Chowchilla Water DistrictP.O. Box 905 Chowchilla, CA. 93601 Doug Welch, Manager (559) 665-3747
Alta Irrigation DistrictP.O. Box 715 Dinuba, CA. 93618-0001 Chris Kapheim, Manager (559) 591-0800
California Energy CommissionRicardo Amon(916) 654-4019 [email protected]
Irrigation Training and Research CenterCalifornia Polytechnic State UniversitySan Luis Obispo, CA. 93407Dr. Charles Burt
(805) [email protected]
This information was developed under the PIEREnd Use Agricultural Sector Program,administered by the California EnergyCommission. It does not necessarily representthe views of the Energy Commission, itsemployees, or the State of California. The
Commission, the State of California, Cal Poly,ITRC, their employees, contractors, andsubcontractors make no warranty, express orimplied, and assume no legal liability for theinformation in this report; nor does any partyrepresent that the use of this information will notinfringe upon privately owned rights.
Irrigation Training and Research Center (ITRC) - www.itrc.org
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Thisreportwas preparedaspartofCECContractNumber40099014.
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