Septic System Design and Specifications.pdf

May 25, 2020

Permit Reviewers

Lower Colorado River Authority

P.O. Box 220

Austin, TX 78767-0220

OSSF for: Inks Dam National Fish Hatchery, 345 Clay Young Road

Dear Permit Reviewer:

Please find the plans, specifications and calculations for the above referenced private on-site sewer facility.

The facility is designed for five (5) recreational vehicles (RVs) of 320 heated square feet. The RVs will be used for volunteer accommodations up to six months per year. We estimate 48 gallons per day to be generated from each RV. According to the Construction Standards for On-site Sewage Facilities adopted by the Texas Commission on Environmental Quality on December 29, 2016, the combined figure for wastewater design flow with installed low water use fixtures in gallons per day is 240 gallons.

We have designed a low pressure dosing absorption type trench system to serve this residence. The system consists of:

-one, 750 gallon, dual compartment, pre-cast concrete septic tank

-one, 500 gallon, single compartment, pre-cast concrete pump tank -one, ⅓ h.p. submersible pump, Liberty 250 series, 115 volt with alarm and level controls -one, low pressure dosed disposal area with a total of 192 linear feet (five foot credited area which is 960 square feet).

If you should have any questions, please feel free to contact us at 512.756.2028. Thank you for your consideration.

Sincerely, Suzanne Wukasch, R.S. #2724

SEPTIC SYSTEM DESIGN DATA

Disposal Area

Area = 240 gpd ÷ .25 (Ra) = 960 sq.ft. ÷ 5 (36” wide trenches) = 192 linear feet

Profile Hole/Soil Evaluation:

See attached site evaluation form for details on each profile hole. No groundwater was noted in either profile hole on the date of the initial site visit.

Because of the existing soil conditions we are proposing to install a shallow, low pressure dosing trench system on this site. The disposal trenches are to be installed at a depth of 12 - 36 inches and a minimum trench width of 36 inches. The trenches should be level within +/- 1” every 25 feet and three inches total. A stormwater diversion berm is required to direct water away from and around the proposed disposal area.

There will be four, 48 l.f. excavations with one inch (1") Schedule 40 PVC lines each 48 feet in length for a total of 192 l.f. Each line will have 5/32” holes spaced five feet apart on center; there will be approximately ten (10) holes per line. Each hole will generate .41 gpm x 10 holes = 4.1 x 4 lines = 16.40 gallons per minute total.

Dosing Rate = ~ 16 gpm

Total head - For a 80 foot supply line with a 2 inch diameter PVC pipe

1) Friction head = (80/100) x .5 = .40 x 1.2 (fitting loss) = .48 ft.

2) Elevation head = 6 feet

3) Pressure head = 2 feet (at highest line)

Total Dynamic Head = .48 + 6 + 2 = 8.48 feet

Minimum Dosing Volume –

V dose = V supply + 5 (V laterals)

Supply line = 80 feet of 2 inch pipe

V supply = (80/100) x 16.2

= 12.96 gal.

Lateral lines = 192 feet of 1 inch pipe

V lateral = 192/100 x 4.1 gal.

= 7.87 gal.

V dosing = 12.96 + 5 (7.87 gal.)

= 52.32 gallons

Dosing Depth = (gallons per dose/tank volume) x liquid depth (inches)

= (52.32/500) x 36" (13.88 gallons per inch) = 3.77 inches

= 4 inches (actual dose = 55.52 gallons)

Reserve capacity = 36" – 18" = 18" x 13.88 g/inch (500 gal. tank/36" liquid depth) = 249.84 gallons

This system will require a Liberty model 250-Series, ⅓ h.p. pump capable of pumping 16 gallons per minute against ~ 9 feet of head. A ball valve will be used to adjust head pressure at 24 inches in the highest and lowest trench of the disposal area. Do not use metal gate valves.

Septic Tank Data

A total of 750 gallons of storage will be required using a 750 gallon, dual compartment pre-cast concrete tank as the pre-treatment device. The tank must be installed with a minimum separation of five feet from any structure foundation, surface improvement or property line. A minimum separation of one foot is required from all easements. The tank must be level to a tolerance of +/- 1", water tight and set on a level sand pad of a minimum of four inches.

Pump Tank Data

A 500 gallon single compartment, pre-cast, concrete tank will be used as the effluent pumping unit. The tank must be installed with a minimum separation of five feet from any structure foundation, surface improvement or property line. A minimum separation of one foot is required from all easements. The tank must be level to a tolerance of +/- 1", water tight and set on a level sand pad of a minimum of four inches.

Specifications for location of pump activation and alarm floats are outlined in tank detail drawing. As the disposal area will sit at a slightly lower elevation from the pump tank, an antisiphon hole is required in the pump supply line. A check valve is also required in the supply line inside or just outside of the pump tank.

A Polylok PL-68 effluent filter (or equivalent) will be proposed and is required. The pump and alarm must be on separate electrical circuits. Electrical service must be hardwired inside the tank with plug fixtures outside. All wiring must be in rigid conduit. The alarm light must be installed where it is visible to the property owner. Both a visual and an audible alarm are required.

We have no objection to the use of a 1250 gallon, three compartment tank with the final, 500 gallon compartment being used as the pump chamber.

A ball valve will be used to adjust head pressure at 24 inches in the highest trench of the disposal area. Do not use metal gate valves.

This system and its layout have been designed based on the “Minimum Construction Standards for On-Site Sewage Facilities” as revised on December 29, 2016 by Texas Commission for Environmental Quality (“TCEQ”) and as amended by the LCRA. These procedures are approved by TCEQ and LCRA and indicate only that a system can be installed here, which meets the estimated flow rates established by the State of Texas. The proper performance of this system cannot be guaranteed even though all provisions of the Standards have been met. Owner is ultimately responsible for the system upkeep (retaining maintenance, reporting problems, monitoring flow, etc.). While the designer has made diligent effort to preserve vegetation and the landscape, the designer is not responsible for any losses (trees, landscaping, etc.) due to installation, operation, and/or system failure.

SYSTEM MAINTENANCE

1. Water conservation is very important in protecting your septic system from failure. Low flush toilets (1.3 gallons/flush or less) and water restricting shower heads and faucets are required for this system.

2. Avoid using a garbage grinder as this tends to increase the amount of fats, grease, and floating scum in the tanks and can clog lines.

3. Septic tanks require periodic pumping. It is recommended that the tanks be pumped every three to five years, depending on usage. If an alarm condition exists, avoid further use of system until the pumping chamber is pumped and a licensed installer can make the necessary repairs.

4. This system is designed to treat and dispose of domestic wastewater only. The property owner should not dispose of any products in the treatment system which could disrupt the treatment and/or disposal process. Those items include but are not limited to commercial enzymes, yeast, water softener back flush, etc.

5. Vegetation on the drain fields is a necessity. Grasses help in the evapotranspiration process. Keep grass mowed and maintain a "healthy" lawn over the drain fields.

6. Don't allow vehicles or heavy equipment to drive over drain fields.

7. The pump tank is equipped with an electric motor and alarm circuitry. The alarm is to warn the homeowner of a failure in the pumping system. If an alarm condition exists, avoid further use of the septic system. First, check pump circuit breaker and electrical connections. If these appear to be functioning properly, contact a licensed waste hauler, pump the tanks, and call a licensed installer to address the situation.

8. Do not create an impervious cover (i.e. sidewalks, driveways, patios, decks and above ground swimming pools) over your septic system. A large part of the continued proper functioning of the system requires it to be exposed to sunlight and vegetation.

9. If an effluent filter is installed with this system, the homeowners are to check the filter routinely and clean as necessary.

CONSTRUCTION NOTES

1. Construction materials, specifications and all construction methods shall conform to the requirements set forth in the Construction Standards for On-site Sewerage Facilities, Texas Commission on Environmental Quality, December 29, 2016 and City of LCRA's Rules, Regulations and Construction Standards.

2. The installer must be licensed by the State of Texas and must have the governing authority and the designer to inspect the system at the required construction intervals.

3. Schedule 40 PVC must be used for all pipe in this system: inlet, outlet, supply line and field lines. Quick disconnect couplings must be provided to facilitate pump replacement.

4. An automatic sprinkler system must not be installed over/in the drain field area. All sprinkler system components must maintain a minimum 10' distance from all septic system components (this includes pipe, tanks and drain field).

5. Low-flow fixtures should be installed in faucets and shower heads. The use of 1.3 gallons/flush toilets are required.

6. All water supply lines must maintain a minimum of 10 feet from any septic system components.

7. Vegetation must be immediately established on the drain field. Proper care (regular mowing, watering and fertilization) of the vegetation is a necessity for effective evapotranspiration.

8. The pump and alarm must be on separate electrical circuits. Electrical service must be hardwired inside the tank with plug fixtures outside. All wiring must be in conduit. A lightening surge arrestor is recommended for the pump circuit. The alarm light must be installed where it is very visible to the property owner. Placement outside or in a high traffic area (i.e. laundry room) is recommended. Both a visual and an audible alarm are required.

10. All electrical installation must comply with NEC standards and local code.

10. Tanks buried more than 12" must have a riser installed by the septic installer.

11. Tanks under driveways must have traffic bearing lids. All PVC supply lines beneath paved surfaces, used as traffic-bearing areas, must be sleeved in the next greater size of PVC.

12. All septic tank and pump tank inlets/outlets must be thoroughly sealed with waterproof sealant.

13. A cleanout is required between the foundation stub-out and the treatment tank. An additional cleanout shall be provided every 50 feet on long runs of pipe and within five feet of 90° bends.

14. A 6", 45 degree turn-up with screw on cap is required at the end of each trench line.

15. Effective September 1, 2012, applicable to all pretreatment tanks, proprietary treatment units, non-standard treatment units, pump tanks, holding tanks and septic tanks:

All inspection and cleanout ports and cleanout ports for septic tanks buried 12" deep or greater shall have risers over the port openings which extend to the ground surface. A secondary plug, cap or restraint system shall be provided below the riser cap to prevent tank entry if the cap is unknowingly damaged or removed.

The rules remain unchanged for septic tanks buried less than 12".

Risers must be permanently fastened to the tank lid.

Risers must be fitted with removable watertight caps that are secured by a padlock or a cover that can be removed with tools or a cover having a minimum weight of 65 pounds set into a recess of the tank lid.

Risers and caps exposed to sunlight must have ultraviolet protection.

Risers must be able to withstand pressures exerted by surrounding soil.

Installation of a riser shall be performed by a licensed installer.

Any person who accesses secured lids or covers shall secure the lid when access is complete.

Inspection reports sent to authorized agents, regional offices and homeowners must document that the access was secured after activities were completed or that the OSSF system owner refused to pay for repairs that were needed to secure the cleanout ports.

Pump Specifications

250 Series Submersible

Sump / Effluent Pump

0 10 20 30 40 50

GALLONS PER MINUTE

T O

T A

L H

E A

D I N

F E

E T

0.0 0.5 1.0 1.5 2.0 2.5 3.0

LITERS PER SECOND

T O

T A

L H

E A

D I N

M E

T E

R S

250_P1 R4/23/2010 ©Copyright 2010 Liberty Pumps Inc. All rights reserved. Specifications subject to change without notice.

P .O . B ox 220 S -204P , A u stin , TX 78767

(512 ) 473 -3216 o r 1 -800 -776 -5272 , E x t. 3 216

F ax (5 J2 ) 473 -3501

2643 N . W irtz D am R oad , M arb le F a lls , TX 78654

(512 ) 473 -3216 o r I-R O O -776 -5272 , E x t. 3 216

F ax (830 ) 693 -6242

L ow er C o lo rado R iv e r A u tho rity

SO IL ANA LY S IS FO R AN ON -S IT E SEW AGE FA C IL ITY

T he fo llow ing in fo rm a tio n m ust b e subm itted w ith th e app lica tio n p ack ag e fo r rev iew by LCRA .

F a ilu re to in c lu d e o r add re ss a ll o f th e fo llow ing item s m ay re su lt in app rov a l d e lay s .

C oun ty BURNET

S ite In fo rm a tio n S ite E va lu a to r

C oun ty

SUZANNE WUKASCHN am e o f O w ner N am e

BURNET, TX 78611

S ite A dd re ss A dd re ss P.O. BOX 401

C ity , S ta te , Z ip C ity , S ta te , Z ip

P hone N o . P hone N o . 512.756.2028

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US GOVERNMENT

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345 CLAY YOUNG ROAD

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BURNET, TX 78611

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BURNET

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NONE

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NONE NOTED

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YES

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CLASS II

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NONE

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NONE NOTED

Suzanne Typewritten Text ~ 5%

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YES

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MARCH 12, 2020

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CLASS II

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