Type of Project.
The City of La Feria, Texas is proposing a water and wastewater improvement project that will include building an upgraded water treatment plant, a new wastewater treatment facility, new water distribution lines, new wastewater collection systems and purchase of water rights for the entire City’s service area. The work will include providing services to eight colonias, six of the colonias have City water but no wastewater service, and two have neither City water nor wastewater services. The eight colonias are located towards the north and west side of the City. The Colonias are La Feria Gardens, Nancy & Soliseno Subdivision, North La Feria Village, Sierra Alto Subdivision, Palmera Heights, Valle Verde Subdivision, Windsong Village, and BR Subdivision.
The estimated cost of the design and construction of the water and wastewater system improvements is $13,239,359, the purchase of water rights is estimated at $1,650,000, and the Capital Improvements Plan considers $ 3,750, 000, giving a total project cost of $18,639,359. The project facilities and water rights purchase will accommodate the City’s growth, as projected by the TWDB, to 2023.
Location
of Project
The City of La Feria is located in western Cameron County approximately 8 miles north of the U.S./Mexico international border close to Expressway 83 between Harlingen and Weslaco. The existing water and wastewater treatment plants are on Dodds Lane one mile south of the City. The project is located within the 100-kilometer border region as defined by the La Paz agreement. The City’s 2000 population was 6,115 (2000 census) and 1,172 for the “colonias”. It is projected to increase to 9,283 for the city and 1,623 for the “colonias”, for a total population of 10,906 within the next 23 years. The population growth rate is 1.83%. The average water consumption is 137 gpcd (gallons per capita per day ).
Description
of Project and Tasks
The water distribution system improvements include 4.86 miles of water mains, 2.13 miles of water distribution lines, and expansion of the existing 2.0 MGD (million of gallons per day) water treatment plant by 1.45 MGD. The additions to the wastewater collection system will include 4.9 miles of collection lines, 119 manholes, 3.4 miles of force main and a new 1.25 MGD wastewater treatment plant. The plant is located on a 10-acre parcel of land on the east side of Rabb Road and approximately one-half mile west of the existing facility. The old treatment plant will be decommissioned and the proposal is to use the 26 acres of wastewater lagoons for wildlife refuge and/or storm water storage.
The construction of the work will be let under several contracts. The design and construction work will be phased to ensure the water and wastewater plants are completed and commissioned before connecting to the new water distribution and wastewater collection system.
Compliance
with International Treaties and Agreements.
The project complies with the agreements that the United States and Mexico have signed, such as the La Paz Agreement, Border XXI Program and North America Trade Agreement.
Human Health/Environmental Needs.
The project will address the human health needs by eliminating potential risks to public health and safety caused by the unsatisfactory water and wastewater problems in the eight Colonias. The Texas Department of Health performed an Environmental Health Survey and Evaluation of the eight Colonias in August 2001. The reports for all the Colonias stated, “The following conditions were observed and appear to be in violation of Chapter 341 of the Texas Health and Safety Code and could be considered dangerous to the health and safety of the people that live in the community.” In reference to the Texas Department of Health’s guidance for nuisance findings for Economically Distressed Area Program (EDAP), the report noted one or more of the following situations were present in the Colonias:
Water quality samples were taken in April 2001 in the Nancy/Soliseno Subdivision where the residents use well water and have on-site septic systems. The results indicated the water was unsuitable for drinking and should be treated, coliform organisms were present and there was heavy confluent growth. The same results can be expected in the remaining Colonias as all have on-site septic systems.
The Texas Department of Health keeps records of countywide health statistics, but no information is available for the La Feria area. The following tables indicate the number of new cases of waterborne diseases for Cameron County and waterborne diseases per 100,000 population.
Reported
Waterborne Disease Cases
Cameron County
|
Disease
Cases |
1997 |
1998 |
1999 |
|
Amebiasis |
24 |
20 |
0 |
|
Campylobacteriosis |
13 |
12 |
28 |
|
Salmonelosis |
41 |
51 |
48 |
|
Shigelosis |
59 |
134 |
77 |
|
Hepatitis A |
273 |
217 |
184 |
|
Hepatitis B |
26 |
25 |
17 |
|
Hepatitis C |
4 |
13 |
0 |
Reported
Waterborne Disease Rates (cases per 100,000 population)
Cameron County
|
Disease Rate |
1997 |
1998 |
1999 |
|
|
Amebiasis |
County |
7.7 |
6.2 |
0.0 |
|
Statewide |
0.8 |
0.4 |
0.2 |
|
|
Campylobacteriosis |
County |
4.2 |
3.7 |
8.5 |
|
Statewide |
5.1 |
4.5 |
5.8 |
|
|
Salmonelosis |
County |
13.1 |
15.9 |
14.6 |
|
Statewide |
14.5 |
17.3 |
11.0 |
|
|
Shigelosis |
County |
18.9 |
41.9 |
23.5 |
|
Statewide |
18.1 |
20.3 |
11.4 |
|
|
Hepatitis A |
County |
87.4 |
67.8 |
56.1 |
|
Statewide |
23.4 |
18.0 |
12.6 |
|
|
Hepatitis B |
County |
8.3 |
7.8 |
5.2 |
|
Statewide |
6.4 |
10.0 |
4.3 |
|
|
Hepatitis C |
County |
1.3 |
4.1 |
0.0 |
|
Statewide |
1.9 |
2.4 |
1.8 |
|
The project will rectify the operational concerns at the wastewater treatment plant. The plant does not meet the Texas Commission on Environmental Quality’s (TCEQ) BOD (Biochemical Oxygen Demand) and TSS (Total Suspended Solids) standards when releasing the treated water. However the plant is presently operated so the facility is not in violation with the TCEQ regulations. The addition of the wastewater discharge from the eight colonias and the growth in the City’s population will result in the plant not being able to be operated without violating the TCEQ discharge regulations for BOD, TSS and coliform. This would result in degrading the receiving body of water, which is the Arroyo Colorado, which will discharge into the Gulf of Mexico.
Environmental
Assessment
The Environmental Information Document has (EID) been prepared for the City of La Feria for the project. The EID and the Engineering Facility Plan has been reviewed by the EPA which issued the Finding of No Significant Impact on November 26, 2002.
Compliance with
Applicable Environmental and Cultural Resource Laws and Regulations.
The proposed project has complied, or will comply, with all necessary environmental and cultural resource laws. The following agencies and governmental entities were contacted and input obtained during the preparation of the EID: Texas Parks and Wildlife Department, United States Department of the Interior, Fish and Wildlife Service, Texas Historical Commission, Texas Water Development Board, Texas Commission on Environmental Quality (formerly the Texas Natural Resource Conservation Commission), Texas Department of Transportation, Texas Natural Resource Information System, Texas Department of Health, United States Army Corps of Engineers, United States Environmental Protection Agency, Federal Emergency Management Association, Cameron County Irrigation District No. 3 (La Feria), Cameron County Engineering Department, North Alamo Water Supply Corporation, and The City of La Feria.
Appropriate Technology.
The City obtains its water from the La Feria Irrigation District, which takes the water from the Rio Grande. The City’s point of withdrawal is the City’s water treatment plant located on the West side of the Intersection of FM 506 on Dodd Lane. The City is entitled to a water allocation of 1,800 acre-feet per year (1.61 MGD) from the Irrigation District. The City has proceeded to install a water well that has a capacity of 1.5 MGD. The intent of the water well is as a drought contingency measure. Surface water is the preferred option for water supply. When the projected water usage was assessed for the period 2002 to 2015, assuming only surface water, the worst-case scenario indicated additional water rights would be needed in 2003.
The City operates and maintains a 2.0 MGD water treatment plant. The treatment plant will be expanded by 1.45 MGD to accommodate the projected demand and the new units will be built parallel to the existing treatment train. The units in the new treatment train will be: a clarifier of diameter at least 72 ft. (outside diameter) and 12 ft. side water depth; two filters of dimensions 16 ft x 9 ft each; raw water pumps (2 pumps of 505 GPM (gallons per minute) capacity); high service pumps (3 pumps, 3,350 GPM, 2,235 GPM, and 1,120 GPM capacity) with pump building (the minimum pump capacity is 3,348 GPM, the smaller pumps will be required when the largest pump is out of service); chemical building; and backwash settling basins and backwash pumps. The existing two clearwells have a combined capacity of 600,000 gallons, and the clearwell capacity required for the new treatment train is 72,317 gallons. These clearwells will be used to store the treated water from the new train.
The
water distribution system will be sized to meet TCEQ design criteria and City
of La Feria’s subdivision ordinance regulations. The proposed improvements,
based on the results of a computer model analysis and best engineering
judgment, are: an elevated tank of 500,000 gallons capacity was required just
East of Rabb Rd. on the North side of Expressway 83 (note: this tank was
completed in February 2002); a 12-inch PVC water main from the water treatment
plant to the proposed tank site; a 10-inch PVC main from the tank site to serve
La Feria Gardens, Nancy/Soliseno, and Sierra Alto Subdivisions; a 10-inch line
from the tank site to serve the Valle Verde and Windsong Subdivisions; 6-inch
and 8-inch service laterals within the Colonias. In addition to the above
lines, fire hydrants, gate valves, and fittings will be included where
required.
The
wastewater treatment plant will be designed for an incoming pollutant loading
of 200 mg/l and 200 mg/l for
Biochemical Oxygen Demand (BOD) and Total Suspended Solids (TSS), respectively;
and the effluent design standard will be 20 mg/l and 20 mg/l for BOD and TSS
respectively. The discharge from the facility will be to an unnamed drain that
flows into the Arroyo Colorado, which will discharge into the Gulf of Mexico.
The proposed size of the wastewater treatment plant is 1.25 MGD. The principal features of the new plant are:
Headworks - The headworks will be comprised of a
mechanical screen and manual bypass bar screen, degritter, and metering
devices. The mechanical bar screening
system will prevent large debris from entering the treatment units. Debris from the headworks and screening area
will be washed from the screens with the wash water being returned to the
upstream portion of the headworks. The
remaining screenings will be dewatered and disposed of in an on-site dumpster.
Biological Treatment - The Extended Aeration
Treatment system is typically used for smaller communities because of the plant
flexibility and ease of operation. The
extended aeration treatment methodology is used extensively for pre-fabricated
plants because of the ability to construct compact treatment plants and the
simplicity of the operations. The extended aeration process limits the amount
of sludge production to approximately 40 to 60 percent of that of the
conventional activated sludge processes.
Disinfection – The disinfection process for wastewater treatment is the use of the chemical, chlorine, either by injecting or mixing the chlorine into the wastewater. Chlorine is the simplest and most cost effective disinfection process for smaller treatment plants.
Sludge Drying and Disposal – Sludge drying beds are very cost effective where land is readily available. This alternative has low capital and operational cost which requires minimal amount of operator’s attention and skill level. This process is climate dependent, however, the climate in the Rio Grande Valley is classified as a semi-arid and is well suited for this drying method. Preliminary calculations show that approximately 1.3 to 1.9 cubic yards of sludge will be produced daily at the plant capacity of 1.25 MGD (permitted capacity). The City transports the sludge to the BFI Rio Grande Valley Landfill for the present plant where it is disposed of in accordance with TCEQ requirements. The City will adopt the same procedure for the new facility.
The City will decommission the existing treatment plant. This will require the existing influent piping force mains to be relocated to the proposed treatment plant. A new lift station will be located at the northwest corner of the existing treatment plant site (corner of Willow Dr. and Dodd Lane).
The wastewater collection system will be by gravity, except where lift stations are needed to overcome terrain or system location constraints. The proposed collection system for the Colonias will be independent of the City’s existing collection system. The new system will connect to the present system at a lift station (a duplex grinder pump station to reduce the construction costs) and then piped directly to the wastewater treatment plant. This approach of keeping the new system separate from the City’s existing network was preferred as this system sometimes overflows in time of heavy rains. The lift stations design are based on the average and the 2-hour peak flows. The wet well size will be designed for a two-hour electrical power outage and to accommodate the peak flow with one pump out of service.
Operation and
Maintenance Plan
The Operations and Maintenance (O&M) manual which will be prepared by the City’s engineer as one of the projects activities and describe the actions and corrective measures to be taken should a contingency or emergency occur during start-up and the operational phases of the project. The O&M manual will be completed prior to the completion of the water and wastewater plants. The City’s staff will receive training prior to, and assist in the startup and commissioning of the facilities.
Compliance with
Applicable Design Standards and Regulations
The project will comply with the applicable design standards and regulations for water and wastewater projects issued by the TCEQ and TWDB, and other applicable local, state, and federal governmental entities. The design drawings and contract documents will be reviewed and approved by the TCEQ and TWDB prior to being issued for bidding for construction and procurement of the equipment. The TWDB and NADB (North American Development Bank) will review and approve the negotiated contracts before making the award.
Financial
Feasibility and Project Management
Financial Feasibility. The financial analysis determined the following funding structure of the project and the user rates to guarantee the financial sustainability of the operating agency.
|
200-2001 Water and Sewer Expenses |
|||
Concept
|
Amount
(US$) |
||
|
|
Operating
Revenue (Water and Sewer) Operating
Expenses (Water and Sewer) Non-operating
Expenses (Water and Sewer) |
1,091,057 943,102 (6,639) |
|
|
|
|
Net Income
|
$
141,316 |
|
Estimated Cost |
|||
|
Concept |
Amount (US$) |
||
|
|
|
Water System |
4,465,684 |
|
|
|
Wastewater System |
8,773,675 |
|
|
|
Water Rights |
1,650,000 |
|
|
|
Capital Improvement Plan |
3,750,000 |
|
|
|
Total |
$18,639,359 |
Rate Model: The rate model was developed by NADB, and the results are presented in the following table.
|
SINGLE FAMILY RATES (US$) |
|||
|
|
2003 |
2004 |
2005 |
|
Average Monthly Water Bill |
$
22.80 |
$ 23.94 |
$ 25.13 |
|
Average Monthly Sewer Bill |
$ 16.35 |
$ 17.15 |
$ 18.01 |
|
Total Bill |
$ 39.15 |
$ 41.09 |
$ 43.14 |
|
|
2006 |
2007 |
2009 |
|
Average
Monthly Water Bill |
$ 26.38 |
$ 27.69 |
$ 30.52 |
|
Average
Monthly Sewer Bill |
$ 18.91 |
$ 19.85 |
$ 21.88 |
|
Total Bill |
$ 45.29 |
$ 47.54 |
$ 52.39 |
|
Source |
Amount
(US$) |
% |
|
TWDB- EDAP
(grant) |
5,144,359 |
28 |
|
TWDB - CWSRF (loan) |
385,000 |
2 |