Flap Gate - Irrigation Training and Research

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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.



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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.

mailto:[email protected]:[email protected]


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Thisreportwas preparedaspartofCECContractNumber40099014.

Flap Gate - Irrigation Training and Research

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