CHAPTER 9 Water and Wastewater System Introduction There are three major water and sewer providers within the city limits and extraterritorial jurisdiction of Harlingen. The main provider of both sewer and water and is Harlingen Waterworks. A secondary water provider is East Rio Hondo Water Supply Corporation providing water mostly north and east of the city limits. The third water supplier and second sewer provider is Military Highway Water Supply Corporation. They provide services primarily south of the city limits and within the city limits strip extending south along FM509. A map of the three major provider service areas is included. Figure 9-1 illustrates water service areas (often referred to as areas of Certification of Convenience and Necessity or CCN). Figure 9-2 illustrates wastewater service areas. Harlingen Waterworks The Harlingen Waterworks System (HWWS) is a division of the City of Harlingen. The system operates under a general manager with a Board of Trustees appointed by the City Commission of Harlingen. HWWS provides potable water service to customers within the City's water certificated area, which is established by the Certificate of Convenience and Necessity (CCN) issued to HWWS by the Texas Natural Resources Conservation Commission (TNRCC). HWWS also sells treated water to wholesale customers, which include the City of Combes, the Town of Palm Valley, the City of Primera, the East Rio Hondo and Military Highway Water Supply Corporations and emergency water to La Feria and San Benito. HWWS provides sanitary sewer service to areas within the sewer certificated area, which is established by the CCN issued to HWWS by TNRCC and sewage treatment for Combes and Primera. While the majority of the area within the existing City Limits of Harlingen is presently served by the City's sewer system, much of the area to the west of the city does not currently have municipal sewer service although development partnerships between developers and HWWS are expanding sewer to this area rapidly. HWWS must adhere to the Federal and State laws and regulations governing water and wastewater utilities in the State of Texas. As regulations change, HWWS must continue to make changes in the system to provide a safe drinking water supply and to clean the wastewater in order to protect the waters of the State of Texas. Raw Water Source The City of Harlingen has one source of water to supply the needs of the community and the customers it serves. As with all entities in the area, Harlingen obtains its raw water supply from the Rio Grande River. Water is transmitted to Harlingen through canals of the Harlingen Irrigation District. Water Rights Under Texas law, a municipality or other user is allowed to use water based on the amount of water rights that it owns. Once the annual water rights allotment has been used, a user cannot use additional water without purchasing or leasing from other users' water rights. Harlingen currently has a total allocation of 21,338 acre-feet of water rights per year. While transporting this water from the Rio Grande through canals, pipelines and reservoirs, 15 percent of the use is charged to the City to account for water losses in the system. Therefore, the net amount available for use by the City is 18,137 acre feet per year, which is an approximate average of 16 million gallons per day. In 2000, the amount of raw water billed to the City was an average of 14.9 million gallons per day (mgd) or 78.1 percent of the available water rights. Wholesale customers served by the system must provide their own water rights for their use. Raw Water Storage Reservoirs The raw water is delivered to the storage reservoirs at each of the two water treatment plants in Harlingen. The reservoirs provide several benefits to the City, which include providing an emergency supply of water, taking water when water quality is best, and storage of water when there is no charge to the City's water rights allocation (free pumping). At the Downtown Treatment Plant, the reservoir (known as City Lake) has a total storage capacity of 30 million gallons or 92 acre-feet. The Downtown Treatment Plant was expanded in early 2001 to 20 mgd. At this rate the reservoir would provide approximately 1.5 days storage without additional inflow from the canal. The other plant, M.F. Runnion Water Treatment Plant, has a reservoir with a capacity of 295 million gallons or 905 acre-feet. At a treatment plant capacity of 20 mgd, this equals approximately fourteen days of storage. Safe Drinking Water Act The Safe Drinking Water Act (PL 93-523) was enacted by the U.S. congress in 1974. As a result of this act, the United States Environmental Protection Agency (USEPA) promulgated the National Primary Drinking Water Regulations (NPDWRs). Subsequently, Congress passed the 1986 Amendments to the Safe Drinking Water Act. These amendments directed the USEPA to add an additional 83 contaminants to the list of regulated compounds by 1989, and 25 additional contaminants every three (3) years thereafter. The USEPA has responded to this directive by promulgating a number of new drinking water regulations and is in the process of preparing additional rules. Water Treatment Plants HWWS operates two water treatment plants in Harlingen. The Downtown Plant, located near the center of the City, was originally constructed in 1928, by Central Power and Light Company (CPL). In 1945, HWWS purchased the water system from CPL. Major improvements have been made in 1952, 1956, 1988 and 2000- 2001. The capacity of the Downtown Water Treatment Plant will be 20 mgd by the end of the year 2001. The M.F. Runnion Water Treatment Plant, located on Dixieland Road in the southwest portion of the city, was originally constructed in 1972. In 1988, the Runnion plant was expanded to its current capacity of 20 mgd. A water treatment plant should be sized to meet the system's maximum day demand. In 2000, the maximum day demand occurred in July, when the Downtown Treatment Plant treated 6.3 million gallons and the M.F. Runnion Plant treated 17.8 million gallons. The combined total of 24.1 million gallons equals to 89 percent of the system's total 27 mgd treatment capacity or 60 percent of the total 40 mgd capacity when the Downtown expansion is complete in 2001. The Downtown Water Plant expansion should provide sufficient capacity through year 2015 assuming current growth rates prevail. Water Treatment Processes Raw water storage, described previously, assists in settling of sediment contained in the raw water delivered to the reservoirs, with added benefits of oxidation and sunlight. Storage can also cause the growth of algae and other organisms, which affect the taste, odor and color of the water. Aeration is used to strip the gases and organics from the raw water prior to treatment. Copper sulfate is also used to control the growth of algae in storage reservoirs during the summer months. M.F. Runnion Water Treatment Plant Chemical addition and rapid mixing are provided to introduce chemicals used for settling in subsequent processes. Typical chemicals include the use of polymers and aluminum sulfate (alum). The rapid mixer provides agitation to completely introduce the chemicals to the incoming raw water. The water then goes through a gentle mixing zone to allow the particles to coagulate or join together prior to settling in reactor type clarifiers. The clarified water is then sent to dual media filtration consisting of sand and anthracite. This process is required to achieve a turbidity of less than 0.5 nephelometer turbidity units (ntu). The finished water is then stored in underground storage tanks, prior to pumping into the distribution system through a high service pumping station. Other treatment includes the disinfection of the water throughout the plant. This process may include chlorine, ammonia, and/or chlorine dioxide. Caution is exercised in the disinfection process to avoid creation of trihalomethanes (THM's) when chlorine is added to the water. THM's are formed by chemical reaction between organics and chlorine. The use of ammonia helps to prevent this reaction. Powdered activated carbon, fed in a liquid slurry, is used in the process to improve the taste and reduce odor in the water. Downtown Water Treatment Plant Raw water storage for the Downtown Plant is the same as the M.F. Runnion storage except it does not use aeration. Raw water is pumped through a static mixer that mixes the chemicals added. These chemicals include aluminum sulfate (alum), and permanganate. The raw water then flows to two ActiFlo, patented water treatment units each rated at 10 mgd. These are the first treatment units of their kind in the state of Texas. These treatment units combine the alum floc with a polymer and sand to create a sand ballasted floc with enhanced settling properties. Mixing chambers develop the attachment of sand to the floc. The flow then goes through a settling basin and tube settlers. Flows after the settling basin are treated with chlorine dioxide, powdered activated carbon for taste and odor control and are chlorinated. The chlorinated water is then filtered and stored in underground storage tanks. A high service pump station then pumps the stored water to the distribution system. Both treatment plants have emergency generators for use in the event of power outages. Water Transmission and Distribution System The water distribution system consists of water mains and lines constructed of a variety of materials including cast iron, asbestos cement, PVC, and concrete steel cylinder. These pipelines range from 4 inches to 30 inches in diameter. The locations of major distribution lines and tanks as well as proposed improvements are shown in Figure 9-3.The distribution system has three elevated storage tanks and two surface storage tanks with high service pumps. The elevated tanks ride on and maintain distribution pressure. The two surface storage tanks have pumping facilities to bolster pressure and have approximately two-day storage under emergency conditions. The Treasure Hills surface storage tank has an emergency generator for use in the event of a power outage. This 10 million gallon tank can provide water for the hospital and residences on the south side of the Arroyo in the event of a major catastrophe that separates the water systems on the north and south sides of the Arroyo. The surface storage tanks and their pumping stations equalize the pressure gradients of the distribution system. Water System Plan A detailed water system plan for HWWS was prepared in 1984, entitled "Water System Analysis" by Kindle, Stone & Associates, Inc. HWWS has since made modifications due to changing development. This section of the Vision 2020 Comprehensive Plan Chapter has been updated by HWWS and utilizes previous studies and in-house studies to summarize the needs of HWWS and extrapolate current projections from previous findings. Table 9-1 EXISTING ELEVATED STORAGE FACILITIES Harlingen's Vision 2020 Comprehensive Plan Harlingen, Texas High Water Level Low Water Level Location Capacity (mg) (msl) (msl) Pendleton Park 1.25 171.7 127.5 North Loop 1.50 171.0 129.5 Port of Harlingen 0.3 171.7 141.7 Treasure Hills Blvd.* 10.0 Pumps Maintain System Pressure Rio Hondo Road 10.0 Pumps Maintain Sytem Pressure * The Treasure Hills Tank has an emergency generator. Projected Water Demand HWWS's certificated area for water service is unique with respect to the city limits and the comprehensive planning study area. The Waterworks' certificated area extends beyond the city limits to the west of the Harlingen (including the old Stuart Place system). The certificated area is smaller than the planning study area. Other portions of the study area not served by HWWS are certificated for water service by other entities. Assumptions were made to correlate the population projection for areas served by HWWS. The projections of water demands used to determine future planning are shown in Table 9-2. Table 9-2 PROJECTED AVERAGE DAILY WATER DEMAND Harlingen's Vision 2020 Comprehensive Plan Harlingen, Texas Average Population Per Capita Wholesale Total Year Connections Daily (Tbl 2-3B Demand Customers Demand Consumption Units: Meters Persons gal/cap/day MGD MGD MGD 1995 ---- 53,547 170 9.10 1.2 10.76 2000 20,499 62,500 *171 10.70 1.2 11.90 2005 21,102 64,337 **175 11.26 1.5 13.32 2015 24,735 75,412 **190 14.33 1.9 16.95 2020 26,902 82,018 *198 16.24 2.3 19.35 * Includes rural population with water service. ** Source: Harlingen Waterworks System Future Water Supply Needs For the year 2000, HWWS was billed for 16,667 acre-feet of water. This accounts to 78 percent of the total acre-feet of water rights available, which are 21,338 acre-feet. The Rio Grande River supplies the water used in Harlingen. This source of water is shared by many locations along the U.S./Mexico Border region including Mexico. For many years, concerns regarding the amount of water available as well as the water quality have been raised. In the spring of 1995, the Water Master for the TNRCC, issued warnings to users of the Rio Grande that the reservoir level in Falcon Lake were very low and urging water conservation until the reservoir level increased. As the area grows, so does the demand for water. As part of the recommended update to HWWS's water system plan, consideration should be given to alternative sources of water. These could include use of brackish ground water resources in the area, water conservation measures, wastewater recycling and reuse, and capturing excess irrigation and runoff water released to the Laguna Madre. HWWS should continue to acquire additional water rights to increase the City's water supply and serve future demands of the Harlingen area. Water Treatment Requirements A water treatment plant should be sized to treat the maximum day demand in any given year. For the year 2000, data reveals a 10 percent distribution loss. Using a 1.75 peak day to average day ratio and a distribution of 10%, the required treatment capacities for HWWS are shown in Table 9-3. An expansion of the Downtown plant will increase the combined capacity to 40 mgd. According to HWWS records, in July 2000, the combined output from both plants was 24.1 mgd or 89.2 percent of the 27 mgd capacity. HWWS is in construction to increase the capacity of the Downtown Water Treatment Plant to 20 mgd by constructing two mgd ActiFlo units and constructing two new filters. Water Distribution System Improvement Needs HWWS has made substantial improvements to the water distribution system over the past decade. Major "looped" or interconnected transmission mains have been constructed around Loop 499 as well as in the Industrial Air Park on the east side of the city. Transmission mains have been installed to serve the areas west of the city. Table 9-3 PROJECTED WATER TREATMENT CAPACITIES Harlingen's Vision 2020 Comprehensive Plan Harlingen, Texas (D) (A) Average (B) Dist. Loss (C) Demand Treatment Year Metered (E) Capacity Factor Factor Capacity (mgd) (mgd) 1995 10.76 .132 1.75 22.63 27 2000 11.82 .10 1.75 23.57 40 2005 13.32 .10 1.75 29.85 50 2015 16.95 .10 1.75 34.17 60 2020 19.35 .10 1.75 39.01 60 Required Capacity D=[A/(1-B)]xc Source: Harlingen Waterworks System To maintain adequate pressures in the remaining portions of the service area, HWWS should extend and interconnect the transmission lines on the west side of the city. As Harlingen continues to grow into this area, additional improvements will be needed to maintain service to these outlying areas. Figure 9-3 indicates the location of existing and proposed major transmission lines as well as lines down to 12" size required to meet the expected growth in these areas. Treated Water Storage Requirements The purpose of storage in a distribution system is to provide equalization of treatment. In addition to equalization, storage is also needed for fire flow demands. Storage allows the water plants to operate at a constant rate during the day. Plants should be capable of treating the maximum day demand. The storage allows the system to supplement the instantaneous demand when it is greater than the treatment capacity, and is replenished when the instantaneous demand is less than the capacity of the plants. For needed fire flow demands, storage provides the additional water quantity and pressure required for emergency fire fighting situations. Surface storage of two (2) ten million gallon tanks allows for approximately two days of emergency water if treatment is not available or major line breaks interrupt supply. Ground Storage Requirements Ground storage requirements are governed by requirements established by the TNRCC. Additionally, the Texas State Board of Insurance historically has included water storage in its determination of the city?s "key rate" for fire insurance purposes. While these insurance guidelines are not mandatory for sizing water storage facilities, they affect property insurance rates for water system customers. The State Board of Insurance has recently contracted with an outside source for its rate setting functions, which makes the key rating system now obsolete. The new method used to set insurance rates is the Insurance Services Office Public Protection Classification (ISO PPC) system, which does not have a direct correlation of required storage to population. Under the ISO PPC system, water storage is now evaluated on a case-by-case basis. In addition, elevated storage is often beneficial for the reduction of distribution main size by increasing water pressure in the distribution system. The projected future ground storage requirements for HWWS are shown in Table 9-4. Based on the State Board of Insurance requirements, no additional ground storage will be required. With this storage, additional ground storage facilities are not expected to be required to serve the projected needs to the year 2020. Table 9-4 GROUND STORAGE RECOMMENDATIONS (Million Gallons) Harlingen's Vision 2020 Comprehensive Plan Harlingen, Texas Location Existing 2005 2015 2020 Downtown 2.5 2.5 2.5 2.5 Treatment Plant M.F. Runnion 7.0 7.0 7.0 7.0 Treatment Plant Treasure Hills 0.0 0.0 0.0 0.0 Storage Tank Rio Hondo Rd. 0.0 0.0 0.0 0.0 Storage Tank F.M. 800 Storage 0.0 0.0 0.0 0.0 Tank Total Storage 9.5 9.5 9.5 9.5 TNRCC Total Storage 2.0 2.1 2.5 2.7 Requirement (1) Insurance 8.1 8.4 9.8 10.7 Guildeline (2) (1) Requires a total of 100 gallons per connection of ground storage. (2) State Board of Insurance Key Rate requires 130 gallons per person per day. Includes service area outside the city limits. Elevated Storage Requirements Elevated storage requirements for HWWS, in accordance with the TNRCC requirements and fire insurance guidelines, are shown in Table 9-5. The State Board of Insurance required the Waterworks to have elevated storage or groundwater surface storage equal with emergency generators for pumping up to 130 gallons per person for a 10 hour period (or 55 gallons per person per day). The TNRCC requirement is 100 gallons of elevated storage or surface tank storage provided the surface tank storage has auxiliary power for pumping. Table 9-5 ELEVATED STORAGE RECOMMENDATIONS (Million Gallons) Harlingen's Vision 2020 Comprehensive Plan Harlingen, Texas Location Existing 2005 2015 2020 Pendleton Park 1.25 1.25 1.25 1.25 N. Loop 499 1.50 1.50 1.50 1.50 Port of Harlingen 0.30 0.3 0.3 0.3 Treasure Hills ------ 1.5 1.5 1.5 FM 800 ------ ------- 0.5 0.5 Total 3.05 4.5 5.05 5.05 TNRCC 1.7 2.0 2.3 2.5 Requirement (1) Insurance 3.0 3.7 4.3 4.7 Guideline (2) (1) Required a total of 100 gallons per connection of elevated or surface storage tank with auxiliary power for pumping (2) State Board of Insurance requires 55 gallons per capita of elevated storage Wastewater System HWWS provides sewer service to nearly 58,000 residents within the city limits of Harlingen. Most areas outside the city limits but within the sewer certificated area, are not currently served by HWWS. The existing service area is shown in Figure 9-2. Areas that are Harlingen's wholesale water customers are not currently served by HWWS sewer system. There are no sewer facilities in the surrounding towns and unincorporated areas except for the Town of Palm Valley and City of San Benito. These municipalities both have their own wastewater treatment and collection systems. The towns of Combes and Primera have constructed sewer collection systems which tie to a common lift station and force main. The force main is constructed to Harlingen's Wastewater Treatment Plant #2. Harlingen's wastewater flows consist of normal domestic wastewater along with commercial and industrial discharges to the sewer system. HWWS requires industrial customers to pre-treat their wastewater to at least domestic strength wastewater before discharging into the City's sewer system. This requirement allows the treatment of wastewater at the City's two treatment plants to maintain a more consistent effluent quality. The service areas and wastewater treatment plants are shown in Figure 9-4. An area near the center of the city can be diverted to either HWWS plant via the Cleveland Street Diversion Structure. The City's sewer system was evaluated in 1992, by Camp Dresser & McKee, Inc. (CDM) as described in the report entitled "Wastewater Collection System Master Plan." This report summarizes information from previous studies and evaluates HWWS sewerage needs to the year 2010. Wastewater Collection System The existing HWWS wastewater collection system consists of a total of 77 lift stations and approximately 214 miles of gravity sewer and force mains ranging in diameter from 6-inch to 16-inch. Sixty percent of the collection system is constructed of vitrified clay pipe with the remaining lines constructed of PVC. Construction of sewer mains in the area can be difficult due to the presence of a high ground water table. The flat terrain causes the construction of gravity sewers for long main lines to require deep excavation. The shallow ground water table in the area makes the construction of deep sewer mains cost prohibitive. Therefore, the use of lift stations and force mains is required to convey the wastewater to the treatment plants. The locations of the lift stations are shown on Figure 9-4. Of the 77 total lift stations, 57 are submersible pump type. The remaining are the wet/dry pit and self priming pump type . These lift stations and force mains operate intermittently. Long detention times in the system cause the wastewater to become septic prior to arriving at the treatment plants. This septic condition creates hydrogen sulfide gases, which are the major source of odors in the system.HWWS currently has two wastewater treatment facilities in its system. Wastewater Treatment Plant No. 1 HWWS currently has two wastewater treatment facilities in its system. Wastewater Treatment Plant No. 1 is located on the north bank of the Arroyo Colorado, south of the intersection of Commerce Street and Business U.S. 77. The plant was constructed in 1951, with a capacity of 3.1 mgd and is permitted at that capacity today. In 1985, the plant was modified from a trickling filter plant to a combined trickling filter and activated sludge plant. The plant was originally designed to split the flow, with 1.0 mgd flowing through the trickling filters and 2.1 mgd flowing through the new activated sludge units. The trickling filters are no longer in service and all flow is treated in the activated sludge units, with desirable results. In 2003 the Waterworks plans to convert the trickling filters to activated sludge which should increase capacity to approximately 6.0 mgd. Wastewater Treatment Plant No. 2 Wastewater Treatment Plant No. 2 is located on the north bank of the Arroyo Colorado south of FM 106 and east of Loop 499. This plant was constructed in 1960, with a capacity of 3.5 mgd. This plant was originally constructed as a trickling filter plant and was upgraded to a two-stage trickling filter plant in 1981. In 1990, major changes and modifications were constructed at Treatment Plant No. 2. What was known as the original plant was modified to a trickling filter/solids contact plant and tertiary filter to consistently meet effluent standards. In 1997 additional major changes were accomplished at the plant. The trickling filters were changed to activated sludge and the plant capacity was increased to 6.2 mgd. In the future, increases in capacity can be accomplished by adding an additional final clarifier and an additional chlorine contact basin. Additional filters were added to produce a good reverse osmosis feedwater. Currently, HWWS delivers over 3.0 mgd of a 4.0 mgd capacity of "bottle quality" water from wastewater effluent, to a major industry adjacent to the treatment facility (Fruit of the Loom). By reusing the wastewater in lieu of the City's potable water system this "one of a kind" facility saves HWWS the water rights required to serve this industry. After the industry uses the process water, it is returned to a separate section (Section C) of Treatment Plant No. 2, which consists of an activated aeration treatment system. This section of the plant is designed to treat 5.5 mgd of industrial waste combined with 0.5 mgd of municipal wastewater. The treated effluent is discharged into the Arroyo Colorado. HWWS has constructed the largest supercritical water oxidation process in the world and the first unit in the world to process wastewater sludge. The process has been designed to treat the sludges from both wastewater plants, septage from area septage haulers and restaurant grease trap waste. This process is very environmentally friendly and will not utilize landfill space for sludges. Inert solids will be disposed of on permitted property. The sludge process has capacity for additional sludge treatment, which should provide for demand until approximately 2010. Wastewater Flows The analysis of the wastewater flows performed for HWWS indicated the flow characteristics shown in Table 9-6. Minimum, average and maximum day flows for dry weather are shown, as well as the maximum wet weather flow and the maximum monthly average day flow. These characteristics are important considerations in projecting wastewater treatment needs. The average rainfall in Harlingen is 26 inches per year. During periods of heavy rainfall, water inflows into the sewer system cause the flows into the plant to increase. The amount of inflow into the City's sewer system has decreased over the past 10 years due to improvements made in the collection system. Recent flow data for the two wastewater treatment plants indicates somewhat different information than the flow characteristics described in the 1992 CDM report. The flows for calendar year 2000, as measured by HWWS, are shown in Table 9-7. The maximum monthly average flow in 2000 was 7.91 mgd. Table 9-6 WASTEWATER FLOWS Harlingen's Vision 2020 Comprehensive Plan Harlingen, Texas Flow Type Total Flow (mgd) Factor (gpcd) Minimum Dry Weather 4.4 74 Average DryWeather 5.22 88 Maximum Dry Weather 5.62 95 Maximum Wet Weather 11.69 197 Maximum Monthly Average 8.27 139 SOURCE: Harlingen Waterworks System The higher maximum monthly average flow shown in HWWS recent flow information is reflecting the amount of potable water that is used to supply additional process water to the industry as a substitute for recycled effluent. These flows can be as high as two mgd. When potable water is used by the industry, that water is added to the original wastewater flows generated within the City. When the Table 9-7 1994 WASTEWATER FLOWS Harlingen's Vision 2020 Comprehensive Plan Harlingen, Texas Month Plant No. 1 (mgd) Plant No.2 (mgd) Total (mgd) January 1.943 3.280 5.223 February 1.910 4.120 6.030 March 2.230 4.460 6.690 April 2.725 3.860 6.585 May 2.662 3.090 5.752 June 2.618 3.200 5.818 July 2.541 3.300 5.841 August 2.767 3.630 6.397 September 2.760 5.150 7.910 October 2.850 3.820 6.670 November 3.069 3.400 6.469 December 2.989 2.720 5.709 Averages 2.587 3.669 6.256 recycling plant is in operation, the effluent flow to the receiving stream is less. Projected Wastewater Flows For purposes of projecting required wastewater treatment capacity, a combination of information from the 1992 CDM report and current population forecasts are used. By the year 2001, it is expected that HWWS's sewer service area will be expanded to include the Stuart Place area, as well as Primera and Combes. The CDM report utilized higher population projections for the comprehensive plan are used to predict future flows. See Chapter Two for further information on development of the population projections. Wastewater Plant Sizing A wastewater treatment plant should be able to adequately treat the maximum monthly average flow per day expected. This accounts for inflow and infiltration during wet weather and any other seasonal variations in flows. The plant should also be able to treat daily peak demands. Harlingen experiences a slight increase in flows due to the influx of winter tourists between the months of November through March. The CDM report indicated that the maximum monthly average flow in 1990-91 was 5.30 mgd. Based on an estimated population of 52,000, a flow factor of 102 gallons per person per day was calculated. In the year 2000, with an estimated service population of 62,500, and a dry weather, monthly flows were 5.2 mgd. The flow factor is 83 gpcd. This is increased as shown in the table to project for future plant requirements. The results are indicated in Table 9-8. Wastewater TreatmentPlant No. 1 Needs The current plant is rated at 3.1 mgd. However, the trickling filter portion of the plant has been out of service for the last several years. The activated sludge addition made to the plant was completed in 1984. This improvement was designed to treat 2.1 of the total 3.1 mgd capacity. The trickling filter plant is being designed to be converted to an activated sludge plant and increase its capacity to 6.0 mgd. This will suffice until the year 2010. Due to the demand placed on Plant No. 2 for the reuse of wastewater effluent, the common area served by both plants is generally diverted to Plant No. 2. Table 9-8 MAXIMUM MONTHLY AVERAGE FLOW PROJECTIONS Harlingen's Vision 2020 Comprehensive Plan Harlingen, Texas Stuart Total Flow Total Dry Population Primera Combes Year Place Population Factor Weather (Tbl 2-3B) Population Population Area Served (gpcd) Flow 1995 *52,000 2,700 2,600 2,600 *52,000 102 5.30 2000 59,400 3,100 3,000 3,000 *62,500 83.2 5.20 2005 64,337 3,800 3,700 3,700 75,537 85 6.40 2015 75,412 4,500 4,300 4,300 88,512 90 8.00 2020 82,018 4,900 4,700 4,700 96,318 95 9.20 * Population served by the wastewater system is less than that served by the water system; Primera and Combes are not currently served. Service is expected by the end of 2001. Wastewater Treatment Plant No. 2 Needs Wastewater Treatment Plant No. 2 is expected to provide for the future needs of the City. This plant not only provides for thetreatment needs of the City, it also provides the use of recycled water for industry. This is expected to continu e into the future with the area?s finite water resources. By the year 2020, the capacity of Plant No. 2 is projected to be 9.0 mgd. Not included in this figure is the sizing requirement of the reuse treatment area within the plant. HWWS has completed an updating of the existing treatment plant using a cost effective reuse of existing basins conversion to activated sludge. The plant is designed to meet more stringent stream standards recently imposed for the plant's discharge permit. These requirements include a 10 BOD, 15 TSS and 3 NH3. Currently, Treatment Plant No. 2 has the capacity to treat approximately 4.0 mgd of "bottle water quality" effluent to provide process water for industry with the use of reverse osmosis treatment. To provide this amount of effluent for reuse, approximately 5.3 mgd of wastewater must be treated. The remaining 1.3 mgd (brine) is discharged into the treatment plant. A project is under construction to pipe treated water from WWTP#1 to WWTP#2 to increase the amount of water available to be treated by the reverse osmosis system. Wastewater Collection System Needs The wastewater collection system service area is expected to expand to the west of the City and include wholesale service to the Cities of Primera and Combes. A Texas Water Development Grant has funded sewer collection systems for Combes and Primera and a force main along the northern boundary of the City to Wastewater Plant #2. The existing collection system was modeled under future flow conditions by the CDM report. Several of these lines have been reworked by HWWS personnel to remove deficiencies. As indicated in Table 9-9, a total of 10,310 feet of sewer lines were identified as having insufficient capacity to accommodate the projected wastewater flows for 2010 conditions. Based on the population projections of this comprehensive plan, CDM?s 2010 projections would approximate this plan's 2020 flows. Table 9-9 FUTURE COLLECTION SYSTEM DEFICIENCIES Harlingen's Vision 2020 Comprehensive Plan Harlingen, Texas Location Diameter (in.) Length (ft.) 1. From L.S. #9 to New Hampshire St. in New 15 4,170 Hampshire to Hale Ave. 2. In Hale Ave. from Falcon St. to Ed Carey Dr. to 15 3,790 Missouri Pacific Railroad. 18 230 3. In alley between Haine Drive and 23rd St. from Treasure Hills Blvd. to 12 2,120 Clifford Dr. and then to L.S. #5 TOTAL 10,310 SOURCE: Wastewater Collection System Master Plan, Camp Dresser & McKee, Inc., March 1992. Revised by Harlingen Waterworks System, April 2001. East Rio Hondo Water Supply Corporation East Rio Hondo Water Supply Corporation (ERHWSC) is the second of three main water and sewer providers within the Harlingen extraterritorial jurisdiction. It was established in 1979 after the consolidation of two groups of rural citizens of Cameron County, Texas. The goal of all citizens involved was to obtain potable water service for the rural community. Each group started separately, one in the area north of Harlingen with 150 customers, and the other north, east and south of Rio Hondo with 1,000 customers. Each applied separately to the Department of Agriculture, Farmers Home Division for Utilities (FmHA) for funding to establish their potable water system. FmHA recommended consolidation of the two groups, and in 1979 provided grant and low interest loan funding to establish the East and West system. Construction of the two distribution systems and a 1.6 mgd plant was begun in 1980. The north Harlingen area was established as the West system and initially the sole source of water was a wholesale water meter with HWWS. The East system was served by the 1.6 mgd plant. With time, the system has grown from 1,150 meters in 1982 when service started, to over 4,900 in 2001. ERHWSC provides wholesale water to Military Highway Water Supply Corporation (MHWSC), Indian Lake, the United States Immigration and Naturalization Service (INS) Detention Center, and has interlocal agreements for emergency wholesale water to Arroyo Water Supply Corporation, and the City of Los Fresnos. Administration ERHWSC is a non-profit member-owned corporation, established for the development of potable water in rural areas. Every customer with a meter is a member and part owner of ERHWSC. The system operates under a general manager with a Board of Directors, elected by members from nine separate districts within the Corporation's certificate of convenience and necessity (CCN) boundaries shown in Figure 9-1. The board meets at 7:30 p.m., on the first Monday of every month, excluding holidays. The agenda is posted as required by the Texas Open Meetings Act. ERHWSC is developing a set subdivision and line extension ordinance, which will be approved by the Board of Directors. This ordinance with the oversight of the system personnel determines the requirements for subdivisions and line extensions. Any variances from the ordinance or system personnel decisions may be appealed to the Board of Directors at their general meeting during public comments. Water System ERHWSC has over 400 miles of pipe in its distribution system, ranging in size from 2" to 14" (See Figure 9-3) . The original water plant, located one half mile south of FM1561 on Nelson Road, now services the entire distribution system. The plant was expanded to 3.2 mgd in 1997. Raw water for the plant is diverted from a Resaca supplied with Rio Grande River water by a Cameron County Irrigation district Number 2 (CCID#2). The source of raw water is a pump station on the Rio Grande River near Los Indios. The surface water treatment plant uses conventional coagulation, flocculation, sedimentation, filtration, and disinfection prior to storage and pumping to the distribution system. HWWS supplements the north Harlingen area with wholesale potable water through a master meter. The West system was connected to the East system in May 2000, and the supplemental water from HWWS is used only during times of lower pressure. The 1978 contract between ERHWSC and HWWS was originally for 3,000,000 gallons per month (gpm). The contract was amended in 1984 to 6,000,000 gpm. Any amount over the 6,000,000 gallons is charged at a higher rate as overage with an additional impact fee. ERHWSC has three elevated water towers in the distribution system and a ground storage tank at the water treatment plant. The towers are located as follows: (1) 0.1 miles west of Briggs Coleman Road on the north side of FM 508 (250,000 gallons) (2) 1.2 miles east of FM 803 on the north side of FM 106 (200,000 gallons) (3) 0.2 miles west of FM 1575 on the north side of FM 510 (300,000 gallons) The ground storage tank at the water plant has a capacity of 416,000 gallons for a total system capacity of 1,166,000 gallons. Water Rights ERHWSC currently owns 718.898 acre-feet of domestic-municipal-industrial water rights, leases 485 acre-feet, and utilizes 250 acre-feet from a wholesale customer. The Corporation is currently establishing a new 50-year lease contract with CCID#2 for 1,000 acre-feet per year. ERHWSC is also purchasing an additional 1,158.5 acre-feet in 2001 to produce a total available surface water right of 3,612.398 acre-feet of water per year. The maximum amount of water rights used by ERHWSC was at 2,502 acre-feet in 2000. ERHWSC will have approximately 1,110 acre-feet of water rights for future growth. Future Improvements Future improvements planned include the additional of a new 8.0 mgd surface water treatment plant west of Laureles on FM 510, a new 1,000,000 gallon ground storage tank at the existing plant on Nelson Road, a new 1,000,000 gallon ground storage tank and pumping station near the INS Detention Center, and new larger distribution lines on FM 510, FM 803, FM 1847 and Stanford Road. As development continues, additional water towers or ground storage pumping stations will have to be strategically located and constructed. Long-range planning includes the potential to build an additional water treatment plant in the North Harlingen area with expanded storage and distribution capacity in that area as well. Sanitary Sewer System ERHWSC has established a CCN for sanitary sewer service (see Figure 9-2) and is pursuing colonia funding from the United States Department, Rural Utilities Services, Rural Development. ERHWSC plans to build a sanitary sewer treatment plant near Lozano and provide service to Lozano, Las Yescas, La Tina, and surrounding colonia communities. At this time, the plant and collection system are under design. Military Highway Water Supply Corporation The Military Highway Water Supply Corporation (MHWSC) is the third major water and sewer provider within the Harlingen extraterritorial jurisdiction. It is a member-owned, non-profit corporation incorporated pursuant to the Texas Water Code Chapter 67, Non-Profit Water Supply or Sewer Service Corporation and as supplemented by the Texas Non-Profit Corporation Act, Tex. Rev. Civ. Stat. Ann., art 1396-01, et seq (West 1980, Vernon Suppl 1996 as amended) for the purpose of furnishing water and wastewater utility service. Corporation operating policies, rates, tariffs, and regulations are adopted by the Board of Directors who are elected by the members of the Corporation. History MHWSC provides water service to all the communities and rural areas found along U.S. Highway 281 (Old Military Highway) from the western city limits of the City of Brownsville to the eastern city limits of the City of Pharr (see CCN figure 9-1). Presently, MHWSC supplies water to approximately 7,275 customers in its service areas. The original water system was designed approximately twenty-seven (27) years ago in 1973 to serve less than twenty-eight percent (28%) of the present customers. An expansion to the system was made in 1981 and improvements to the system were completed in 1985, 1993, 1995 and 1999. The major source of supply to the original MHWSC system in Cameron County was the City of Harlingen Waterworks system which supplies a maximum of 600 gpm to a hydro-pneumatic plant located at FM1479 and FM 800. By 1993, the Cameron County service area, which depended on the City of Harlingen for water, required 1,500 gpm. To provide adequate water supply to customers in Cameron County, four wells were developed and used as a raw water source for a Water Treatment Plant built in Las Rusias. Distribution system improvements were also made to meet pressure and quantity requirements for families in the Cameron County service area. The hydro-pneumatic booster station using City of Harlingen water is still in place to supplement the water treatment plant. The Del Mar Heights area consists of a small community east of the City of Los Fresnos and is provided water metered direct from the ERHWSC distribution system using their water storage and pressure. Presently, MHWSC has plans to expand the existing Las Rusias Water Treatment Plant in Cameron County to double its present capacity. MHWSC submitted a complete federal assistance application to Rural Development - Rural Utilities Service in November 2000 requesting financial assistance for doubling present water treatment plant design capacity. Conditions of Existing Facilities The conditions of the existing facilities in each area have been evaluated to determine the suitability for continued use and compliance status with state requirements. In order for a water system to meet Texas Natural Resource Conservation Commission requirements, the supply must provide a minimum of 0.6 gallons per minute of water for each customer served. The plants must have a minimum of 200 gallons of water storage for each customer served and maintain the operating pressure for the distribution system. The pressure maintenance must be a minimum of 20 gallons per customer in pressure tank capacity and booster pumps with a total capacity of two gallons per minute per customer or elevated storage with gravity flow. The distribution system lines must be large enough to provide the required flow of water at a minimum pressure of 35 PSI to each customer at a flow of 1.5 gallons per minute per customer. Cameron County Area The Cameron County area of the system serves 3,956 families with distribution piping in sizes from 16" down to 2" (See Figure 9-3). Supply for the Cameron County area is furnished by four (4) deep wells located in Los Indios and water purchased by a water purchase contract with the HWWS. The maximum delivery rate provided by the water purchase contract is 600 gallons per minute while the production rate provided by each of the four (4) deep wells is 375 gallons per minute. The area has a capacity of 2,100 gallons per minute or 3,500 meter capacity, based on TNRCC criteria. The four (4) deep wells supply water to the water treatment plant located just east of the intersection of U.S. Highway 281 and FM 1479 in the Colonias of Las Rusias. The treatment plant can also treat surface water from the Rio Grande River. MHWSC owns close to 800 acre-feet of water rights that are diverted through the Harlingen Irrigation District. A 10" supply line from the HWWS runs south approximately 20,000 feet to a hydro- pneumatic plant located at the intersection of Rangerville Road (FM1479) and FM 800. This 10" line provides the 600 gpm supply. Storage is provided by a 150,000 gallon ground storage tank at hydro-pneumatic plant, a 1.0 million gallon clear well at the water treatment plant, and seven 100,000 gallon elevated tanks. These elevated tanks are located throughout southern Cameron County. The locations are as follows: 1.) On FM 800 1/8 mile west of FM 2520 (FM800 Tank), 2.) On FM 1479 ½ mile north of US 281 (Rangerville Tank), 3.) Located along U.S. Highway 281 ½ mile each of FM 1577 (Ranchito Tank) 4.) In the community of La Paloma, 5.) In the community of San Pedro, 6.) In the community of Lago 7.) In the community of Santa Maria. The storage capacity is 1,850,000 gallons, or 9,250 meter storage capacity based on TNRCC criteria. Pressure is maintained by five (5) booster pumps totaling 5,000 gpm at the water treatment plant and two (2) service pumps rated at 700 gpm at the hydro- pneumatic plant, which supply the seven (7) elevated tanks with flow of 6,700 gpm. The South Hidalgo County System can supplement this system through a valved interconnection at the county line. The system serving this area is presently being operated using only the water treatment facility. The hydro-pneumatic plant is being maintained with water purchased from HWWS as an option in case of an emergency. When the water treatment plant booster pumps are not pumping, the distribution requirement of 35 PSI minimum pressure is maintained from the seven (7) elevated tanks. Del Mar Heights Area The Del Mark heights area serves 59 families with distribution piping in sizes from 4" to 2". Supply and pressure is provided by a water purchase contract with ERHWSC. Wastewater System Figure 9-2 shows the MHWSC sewer CCN area. MHWSC provides sewer service to families in its service area. In the early part of the 1980's, the first sewerage system was planned to serve the community of Progreso. This sewerage system was put in operation in 1989 and served approximately 370 families. In the last seven years MHWSC has expanded its Central Sewerage Collection System to include most of the communities in its service area. Presently MHWSC provides sewer service to approximately 2,740 families in Cameron and Hidalgo Counties. MHWSC presently operates the following wastewater collection and treatment systems within their service area: 1. Progreso - Progreso Lakes 2. Las Rusias - Los Indios 3. San Pedro - Villa Nueva 4. Santa Maria - Bluetown 5. La Paloma - El Ranchito 6. South Alamo ****** South Alamo collection system and wastewater treatment plant are presently under construction and will be completed by the end of 2001. Condition of Existing Facilities All facilities except the original Progreso Collection Wastewater Collection system were completed within the last five (5) years and are in good condition. Some manholes on the original Progreso System are in need of repair due to gas corrosion. The conditions of all existing facilities were evaluated to determine the suitability for continued use and compliance status with TNRCC. All existing gravity flow lines, force mains, lift stations and wastewater treatment plants are adequately sized and suitable for continued use with the exception of La Paloma Wastewater Treatment Plant. Wastewater generated by families living in the community of Palmer and the growth rate being experienced surrounding the communities of La Palona and El Ranchito due to a booming economy in the Rio Grande Valley has caused the wastewater treatment facility to exceed the design capacity of 210,000 gpd or 2,100 persons/525 families. Presently, La Paloma Wastewater Treatment Plan is treating wastewater generated by approximately 712 families. Based on TNRCC design criteria, a wastewater treatment facility treating the waste generated by a population of 2,848 requires the following design capacity: 2,848 persons x 100 = 284,000 gpd Presently, La Paloma Wastewater Treatment Plan exceeds design capacity by 74,800 gpd or 748 persons or 187 families. Presently, MHWSC has plans to construct a new wastewater treatment in Cameron County. MHWSC submitted a complete federal assistance application to Rural Development - Rural Utilities Service in November 2000 requesting financial assistance for a 510,000 gpd wastewater treatment plant on Joines Road to insure provision of adequate sewer service in the areas south of the City of San Benito. Strive for Ongoing Quality Service Goal 9.1 Continue to build partnerships and encourage mutually beneficial cooperation between systems in order to better provide for the development needs of the region. Goal 9.2 Continue to monitor water and wastewater needs based on population growth and plan ahead to provide adequately for such population.