PDF Format

Prepared for

Brawley’s water treatment system was established more than 70 years ago. It is operated as an enterprise fund, wherein the costs of providing potable water to the general public are funded primarily through flat-rate user charges. The City’s water supply is obtained from the Colorado River, via the 80-mile-long All American Canal and an extensive downstream canal system operated by the Imperial Irrigation District (IID). There are approximately 4,700 active water accounts. Water service to most customers is presently unmetered (less than 2% are metered).

The City’s current water treatment plant will be replaced upon completion of a new treatment plant that is presently in the operation start-up phase. A number of specific technical water treatment processes at the current treatment plant were ruled by the California Department of Health Services to be non-compliant with various state health statutes and regulations.

Brawley’s wastewater treatment system was also established more than 70 years ago. Currently, the system is operated as an enterprise fund, wherein the costs of providing wastewater services are primarily funded through flat-rate user fees which are based upon land use. There are approximately 4,600 active wastewater accounts.

Presently, the wastewater treatment plant (WWTP) is treating effluent in excess of 85% of its maximum capacity, in violation of California Regional Water Quality Control Board requirements. The design capacity of the wastewater treatment plant is 3.9 mgd (million gallons per day). A major portion of the sewer and storm drain system is combined, producing storm flows of 8 to 12 mgd that periodically overwhelm the hydraulic processing capacity of the WWTP.

The wastewater treatment plant consists of a primary treatment facility and a secondary lagoon system that provides liquid and solid treatment processes.. The wastewater collection system also includes two lift stations and 67.3 miles of wastewater collection lines and mains.

In April 1997, Brawley submitted a Step I application to the Border Environment Cooperation Commission (BECC) for the Wastewater Treatment Plant Expansion and Improvements to the Wastewater Collection and Water Distribution Systems Project. The application was reviewed and found to conform with the BECC priorities and objectives. The Step I was accepted and authorization was granted to continue the Step II certification process.

BECC certification is sought by the City in order to have accessibility to the Border Environment Infrastructure Fund (BEIF) administered by the North American Development Bank (NADB). In addition, the City is applying for funding from the Economic Development Agency and others. Through assistance from this process, the City of Brawley will be able to plan upgrades of the existing water delivery and wastewater treatment and collection systems, and help to initiate the process of sustainable economic and community development that will reach all segments of the City’s population.

Water Supply (Distribution). The existing distribution system modifications will eliminate negative pressures in the water system. The modifications include the installation of larger diameter pipes and replacement of cast iron pipes with PVC pipes. This will provide a water distribution system without corrosion and negative pressure problems and properly sized for new planned development. The use of properly sized pipes for the existing and future system will improve the water pressure, reduce the potential of failures and require less maintenance. The estimated capital cost for improvements to the existing system is $18.74 million. However, certification is requested only for the Phase I improvements of the existing system in the amount of $5.61 million.

To meet future water demand requirements, the distribution and storage systems should be upgraded to meet the needs of development to the buildout population of 42,101. The projected cost for expansion of the distribution and storage system is $29.1 million, and for the water treatment plant expansion after year 2014 is $17.2 million. Total future system cost is $46.3 million.

The proposed projects for Phase 1 entail the replacement of 39,627 linear feet of 4- and 6-inch diameter cast iron pipe with 8- and 12-inch PVC pipe. Additionally, 3,209 feet of 4- and 6-inch cast iron pipe will be replaced within City limits with 16-inch PVC pipe to provide services to Po colonia; while 10,093 feet of 8-inch asbestos-cement pipe will be replaced with 18-inch PVC pipe to serve La Colonia. Improvements to the water distribution systems for these two colonias outside of the City of Brawley’s limits will be financed by the U.S. Department of Agriculture as part of their colonias program.

The financial feasibility of a successful twenty-year period ending in the year 2020 for the Water Enterprise Fund is dependent upon certain assumptions:

• The current water service charge rates (in constant dollars) will be maintained;
• The City’s population will maintain at least the "low growth" level to provide adequate service charge revenues;
• Grant funding will be obtained for health related conditions;
• Adequate outside funding will be obtained for future expansion to the water system;
• Final construction estimates will not be exceeded materially.

This project will provide safe, dependable treatment of wastewater for present and future needs. The present wastewater treatment plant has deficiencies that must be addressed. Due to the combined design of the wastewater and storm drain system, large volume flows during storms result in wastewater receiving only primary treatment prior to discharge

Expanding and upgrading the WWTP will decrease the likelihood of discharging raw sewage into the New River and reduce disease transmission through casual contact with raw sewage, as has happened in the past. The proposed project will increase capacity so that the increased flows that occur during storms can receive both primary and secondary treatment prior to discharge. It will also permit discharge of wastewater effluent that has been treated to a higher degree than currently possible.

The City is required by the California Regional Water Quality Control Board (CRWQCB) to expand the plant capacity since current flows exceed 85% of the design capacity of 3.9 mgd. The plant is in need of additional capacity to accommodate existing demands and near-term development. In addition, failure to take action could result in a penalty of $10,000 per day per violation and other legal concerns/costs associated with the violations. Disinfection facilities need to be added to the treatment process in order to comply with the expected requirements of a future state permit.

The estimated wastewater flow volumes are based, in part, upon information provided in the 1995 Brawley General Plan. See Table below.

The current permitted effluent requirements are Biochemical Oxygen Demand (BOD) - 45mg/l, Total Suspended Solids (TSS) - 95mg/l, settleable matter - 0.3 mg/l, and average daily flow - 3.9 mgd.

As determined by Roy F. Weston, Inc. (WESTONâ ) in the Master Plan for the Wastewater Treatment Plant, the aerated lagoon process was the most favorable alternative. All of the alternative criteria were weighed in an evaluation matrix. The aerated lagoon process scores equal to or higher than the other alternatives in all criteria. The aerated lagoon process is the system currently utilized at the WWTP. Therefore the technology is known by the current operating personnel.

There is a disinfection process requirement expected with the upcoming National Pollution Discharge Elimination System (NPDES) permit. WESTON evaluated three disinfection process alternatives and found Ultraviolet (UV) to be the most favorable, provided the UV system is reevaluated following a minimum 30 day pilot testing period. This pilot testing should be conducted during the design phase of the system. The UV scored most favorable in an evaluation matrix in "safety concerns" and "Installation and O & M costs". The table below displays the estimated capital costs for the wastewater treatment Certification is requested for the Phase 1 Expansion and Phase 1A Disinfection totaling $7,173,000.

Wastewater Collection System

The City’s wastewater collection system was established more than 70 years ago. Approximately 1,500 acres of the City has a combined storm drain and sanitary system. The results of the analysis in the Master Plan for the Wastewater Collection System indicate that 33% of the collection system lines are undersized when the present system was simulated as the present combined storm drain/sanitary system The recommended capital cost for the collection system were segregated into two categories: (1) replacement and (2) new construction, at $5.5 million and $7.6 million respectively. BECC certification is requested only for the Phase I replacement in the congested areas of the City at an estimated cost of $772,736.

The recommended rehabilitation program includes the replacement of 6,200 linear feet of sewer lines throughout the city.

The recommended method of rehabilitation for line deficiencies that are located in congested areas within the City is removal and replacement of the existing line. Parallel lines are the recommended method of rehabilitation for areas that are predominantly undeveloped.

The financial feasibility of the Wastewater Enterprise Fund’s success during the impending capital improvement program is dependent upon the following:

• The success of the grant funding program to fund replacement cost, environment related costs and expansion needed to support economic growth.
• The success in obtaining low interest rate financing at long-term paybacks.
• The growth of the City’s population over the next 20 years to provide revenues from the wastewater service charges (minimum "low growth" level).
• The success in establishing wastewater service charge rates to obtain the maximum service revenue that is affordable and equitable for the users.
• The success in obtaining expansion dollars from future developers.
• Final construction estimates are not materially exceeded

The NADB developed an evaluation to determine the financial feasibility of the project and to make recommendations regarding the amount of grant the City could receive from such an institution. The following table summarizes the proposed financial scheme.

In addition to BEIF construction assistance funds, the NADB analyzed the possibility of providing BEIF transition assistance to allow for a more gradual increase in rates. Nonetheless, no transition funds were recommended as the required rate increase will not be unaffordable to the community, as described below.

The current water rate is $39.25 per month, while the sewer rate is $12.40 per month. The NADB analysis concluded that the current combined water and sewer rate of $51.65 is relatively high given the economical conditions of the City of Brawley. Thus any significant increase in the combined rate will render the project financially unfeasible. The City has increased water rates from $16.00 a month in 1994 to $39.25 in 1999, or a 145% increase in five years. This increase has been the result of debt incurred by the City of $24 million to finance the construction of the water treatment plant. The only increase in rates recommended at this time will be from $12.40 to $13.00 per month for sewer rates, a 4.8% increase.

As required by the BECC, a public participation process was implemented by the project sponsor. The process included the development of a public participation plan, the formation of a steering committee composed of respected members of the community, the distribution of project information by mail-outs, and holding twelve public meetings throughout the City. Additionally, two city-wide public meetings were held on April 15 and August 4, 1999. The results of the financial evaluation were presented during the second public meeting.

The project is consistent with BECC’s definition of sustainable development: "…conservation oriented social and economic development that emphasizes the protection and sustainable use of resources, while addressing both current and future needs, and present and future impacts of human actions."

All environmental parameters have been met and the increase in water demand and use is consistent with local planning documents. The expansion of the wastewater treatment plant, coupled with the upgrade of the water distribution and wastewater collection systems, will require little in the way of increased institutional capacity, as the proposed treatment technology is very similar to that already in use at Brawley.

City of Brawley Wastewater Treatment Plant Expansion and Improvements to the Wastewater Collection and Water Distribution Systems

3. Primary Applicant Information

Water System The water distribution system is comprised of approximately 75 miles of pipeline within the sphere of influence of the City of Brawley.

Suitability of new site. The Phase 1 improvements to the water distribution system, replacement of portions of the existing system, will occur in the existing pipe alignment which has been serviceable for up to sixty-five years.

Wastewater Treatment Plant The existing Wastewater Treatment Plant is located in the northeast portion of the City, at 5015 Best Canal Road, north of the intersection with Shank Road The planned wastewater treatment plant expansion will be constructed at the site of the current plant (see Site Location Wastewater Treatment Plant).

Suitability of new site. The site is large enough to accommodate the recommended expansion, including aerated lagoons, and is adjacent to the New River to easily accommodate the discharging of treated effluent.

Wastewater Collection System The wastewater collection system, a gravity flow system, approximately 65 miles long, is within the City’s sphere of influence. (See Wastewater Collection System Aerial Photograph, Figure 1-2)

Suitability of new site. The Phase 1 improvements to the wastewater collection system, replacement of portions of the existing system, will occur in the existing pipe alignment, which has been serviceable for up to seventy years.

Project Description. The human health and environmental issues to be resolved by the City’s planned improvements to both the water distribution system and the wastewater collection, treatment and disposal system are as follows.

Water Supply. The existing distribution piping is as much as 65 years old and is comprised of 39% cast iron pipe, 41% asbestos cement pipe (AC) and 20% polyvinyl chloride pipe (PVC). The City has experienced several cast iron pipe failures due to corrosion/tuberculation of the pipe. The corrosion and tuberculation on the interior of the pipes caused significant decrease in the pipe’s capacity, creating excessive pressure losses. The loss of water pressure reduces the ability to deliver the water within the City and causes interruption of water service at times of pipe failures. The City has run fire hydrant tests that measure the flow and pressure at each fire hydrant in its system and has recorded negative pressures during high demand times at several locations. One isolated low pressure reading of 28 psi was recorded at a fire hydrant adjacent to a school. The existence of negative pressures in a water system can result in pipe collapse, the introduction of contaminated water into the system from cross-connections, and the inability to meet user demands.. A replacement program for these pipelines is necessary to resolve these problems.

The City's wastewater collection system, established more than 70 years ago, is primarily a gravity flow system. Approximately half of the system is a combined sanitary and storm sewer system. The system includes two lift stations, approximately 65 miles (345,000 linear feet) of wastewater collection lines ranging from 6 to 30 inches in diameter, and 1.5 miles of force main. All of the collectors and mains flow to the City's Wastewater Treatment Plant (WWTP), which discharges to the New River. The capacity of the sewers is adequate under normal dry weather flow conditions. However, since the majority of the system is combined sanitary/storm sewer, portions of the system surcharge during heavy rainstorm events

Program of Project Work Tasks The following table summarizes the project tasks recommended in the Water Master Plan and the Draft Wastewater Master Plans dated March 1999. The Phase 1 projects in water supply, wastewater treatment and replacement of wastewater collectors, along with estimated costs shown in constant dollars, are included in the certification.

Demographic Information. The water and wastewater systems serve an estimated population of 21,000. Continued moderate growth of Brawley’s population at approximately 1.7% per year is anticipated for the foreseeable future. Commercial, industrial, and residential development anticipated by the City’s 1995 General Plan and 1997 Housing Element predict a 20 year buildout population of between 35,404 and 42,100. The Water and Wastewater Master Plan planned facilities to serve a buildout population of 42,100.

Local Environmental Services. Water and wastewater services availability and supply are provided for 100% of the population.

The Water Master Plan evaluated the water distribution system to determine the adequacy of the existing system for serving the needs of the City of Brawley. Two alternatives were evaluated: (1) no project and (2) the replacement of pipelines on a phased basis

No Project Alternative The distribution system is as much as 65 years old and is comprised of cast iron pipe (CI) , asbestos cement pipe and polyvinyl chloride pipe. The CI is the oldest pipe and accounts for roughly 39% of the total pipe length. Over the years, the City has experienced several CI pipe failures due to corrosion/tuberculation of the pipe. Corrosion and tuberculation on a pipe’s interior can significantly decrease a pipe’s capacity, creating excessive pressure losses. Analysis of the existing distribution system indicates adequate pressures for the annual average demand and peak hour conditions, however during maximum daytime with fire conditions, many areas of the City experience negative pressures.

The existence of negative pressures in a water system can result in pipe collapse, the introduction of contaminated water into the system from cross-connections, and the inability to meet user demands. A replacement program for these pipelines is necessary to resolve these problems. The City has experienced several recent failures in the existing CI pipes due to corrosion. In some instances, when the CI pipe was removed, the pipe’s interior diameter was less than half of what it was when originally installed. The difference in interior pipe diameter equates to greater pressure loss and lower reliability for peak hour and fire flows. If these conditions continue, there will be an increase in distribution failure and the low water pressure will cause stoppages in delivery of water during the emergency situations. Such conditions are not acceptable in a public water system. The Water Master Plan prepared by Pountney & Associates, Inc. (Pountney) examined existing water distribution systems and recommended replacement of the existing pipelines, recommended future expansion of the new WTP, and future construction of new water distribution system.

System Modifications Alternative. To provide adequate pressures during Maximum Day Plus Fire conditions, numerous modifications to the existing system need to be made. The design and construction of the proposed existing system capital improvements are proposed over the next twenty years in four phases. Phase 1 improvements are included in the current project’s Step II certification, and include replacement of all the 4" diameter cast iron pipe and a portion of the 6" diameter cast iron pipes, all the highest replacement priority The following changes are included in Phase 1:

Po Colonia pipe replacement $ 447,327

La Colonia pipe replacement $ 1,520,647

4" and 6" CI replacement $ 3,615,928

Total Phase 1 Improvement $ 5,615,902

Wastewater Treatment

In the Wastewater Treatment Plant Master Plan dated March 1999 (WWTPMP), WESTON evaluated four treatment process alternatives. The four treatment processes evaluated were: (1) No action, (2) Aerated lagoon, (3) Combination aerated lagoon and activated sludge, and (4) Aerated lagoon with reclaimed water.

The selection of these alternatives for review was based on the overall treatment objectives and suitability for the City's needs. All process systems evaluated assumed that screening and grit removal would occur at the headworks of the WWTP prior to the influent entering the first major process equipment.

Wastewater Treatment No Action Alternative The "No Action" alternative was evaluated to identify the necessity of the WWTP improvements and the potential concerns which would be encountered if no action were taken. The WWTP is currently in need of additional capacity to accommodate existing flows. The average daily flow capacity of the plant is 3.9 MGD; the plant is experiencing flows near, or in excess, of this capacity. Flows experienced in September 1998 ranged from 3.91 MGD to 4.27 MGD. This excessive flow resulted in a Notice of Non-Compliance being issued by the California Regional Water Quality Control Board (CRWQCB) on 4 November 1998. The Notice is issued when violations of the City's NPDES permit occur, in this case, the flow constituent. The City is required to take corrective action addressing this concern. Failure to take action can result in a penalty of $10,000 per day per violation and other legal concerns/costs associated with the violations. Since the City is anticipating additional near-term development, the WWTP would also need additional capacity to accommodate the growth. If no action is taken, future development must be postponed until a plan for additional capacity is implemented. This would result in a loss of potential revenue from the developed property and potential fines from the USEPA and CRWQCB.

The aerated lagoon treatment process is the system currently utilized at the WWTP. This system basically consists of the following steps:

• Screening and grit removal (headworks),
• Primary clarifiers,
• Aerated lagoons,
• Stabilization ponds,
• Discharge to New River.

The design of this process is based on a three phase implementation plan consisting of increased capacity increments of 2 MGD, 3 MGD, and 3 MGD to obtain an ultimate treatment capacity of 12 MGD. The Phase 1 to be certified is shown in Figure 2-1

The combination aerated lagoon and activated sludge treatment process would actually be considered two different and separate systems, and operated as such.

The activated sludge process basically consists of the following steps:

• Screening and grit removal (headworks),
• Aeration structure,
• Secondary clarifier, and
• Discharge to New River

See the WWTPMP for the design of this process (Appendix 17, Table 4-3) and a layout of the required facilities for Phase 1(Figure 4-1). These are based on a three phase implementation plan consisting of 2 MGD, 3 MGD, and 3 MGD capacity increases to obtain an ultimate 12 MGD capacity.

The aerated lagoon with reclaimed water process is identical to the aerated lagoon process described above, with the exception of the discharge location. In this process, the effluent would be discharged across the surrounding acreage rather than into New River. This effluent would also serve as irrigation for the agricultural acreage.

The public agencies involved in regulating effluent discharge are the CRWQCB and the Department of Health Services (DHS); the primary agency regulating water reclamation is DHS. The DHS and CRWQCB refer to this overland discharge of effluent as "Reclaimed Water." DHS has established regulations and guidelines for reclaimed water. Effluent parameters established by DHS for reclaimed water, based on agricultural classification, are more stringent than for effluent discharged into New River The more stringent effluent parameters required for reclaimed water will require that the process of the existing WWTP facility be converted to activated sludge. This activated sludge process must also be maintained throughout all future expansions. The capital costs and O&M costs for this alternative would therefore be significantly higher than the aerated lagoon process or combination aerated lagoon/activated sludge process. Consequently the reclaimed water alternative was eliminated from further consideration.

The WWTPMP evaluated the treatment process alternative in an evaluation matrix in Table 4-2 of the WWTPMP (see Appendix 17). The Aerated Lagoon alternative was rated superior in technical issues, area requirements, safety to the operators, and cost related issues. Capital cost and O & M cost were calculated to be less than the other alternatives. Environmental impact potential was the most favorable for the Aerated Lagoon and Combination Aerated Lagoon and Activated Sludge Alternatives. The Aerated Lagoon Alternative is clearly the most favorable alternative. Certification is hereby sought for the first phase increment increase of capacity of 2 mgd.

The WWTPMP evaluated three disinfection process alternatives:

• Chlorination/Dechlorination (gas system)
• Sodium Hypochlorite (Bleach)/Sodium Bisulfite
• Ultraviolet (UV)

The UV was scored as the best alternative in an evaluation matrix. UV scored highest in safety issues, installation/structural cost, and O & M cost. UV scored lowest in reliability at TSS level of 95 mg/L. The actual TSS level discharged from the WWTP has an average monthly value of 37 mg/L, based on 2 years of data. A UV system is more reliable at this TSS level. WESTON recommended that the scoring for the UV system should be reevaluated following a minimum 30 day pilot testing period. The disinfection process considered most favorable after the 30 day UV testing will be part of the certification.

Wastewater Collection System The primary objective of the Wastewater Collection System Master Plan dated January 1999 (WCSMP, Appendix 16) was to evaluate the capacity of the existing sewers under present and future flow conditions. The wastewater collection system, in its current form and condition, is adequate under normal dry weather flow conditions. However, since the majority of the system is combined sanitary/storm sewer, portions of the system surcharge during heavy rainstorm events.

The WCPMP observed that since a majority of Brawley’s collection system is composed of combined sewers, the system is heavily impacted by direct runoff during wet-weather events. During wet weather, the combined portion of the collection system serves as drainage conduits for approximately 1,500 acres of the City. The WCPMP analysis showed that approximately 33% of the collection system lines are undersized when the system was simulated as a combined system. As a separated system, approximately 4% and 27%, of the lines modeled in year 1998 are undersized, in dry weather conditions and wet-weather conditions, respectively. Consequently, improvements to the collection system are warranted.

The WCSMP provided a priority ranking of the replacement of the existing system based on the following assumptions:

• Dry weather deficiencies are more critical than wet weather deficiencies.
• Existing deficiencies are more important than future deficiencies.
• Projects are prioritized by the severity of the deficiency, as measured by the ratio of flow to existing capacity (percent full) for each scenario evaluated.
• A critical deficiency occurs when the flow exceeds 120% of capacity.
• System should be a separate sewer and storm system.

Based on these assumptions, three priority categories for mains were defined:

• Existing dry weather (separated system)
• Percent full, 2020 dry weather (separated system)
• Percent full, 2020 wet weather (separated system)

Each sewer rehabilitation considered was sized for 2020 wet weather flow. 2020 wet weather flow is defined as a 2 year, 5 hour storm event. The system is assumed to be separate sanitary sewer and storm sewer systems. Projects are prioritized by category and ranked by percent full. A critical deficiency occurs when the flow exceeds 120% of capacity. Projects were further ranked according to construction phases. Four construction phases are assumed as follows:

Construction phases are based on the anticipated date of construction for build-outs, or on the available capacity to convey year 2020 wet weather design flow. Rehabilitation projects impacted by new construction are included in the appropriate construction phase.

The recommended method of rehabilitation for line deficiencies that are located in congested areas within the City is removal and replacement of the existing line. Construction of parallel lines is the recommended method of rehabilitation for areas that are predominantly undeveloped.

The total cost of construction projected to the year 2020 is estimated to be $13,115,800. This amounts to an average expenditure of approximately $655,790 per year, until the year 2020. Certification is being sought only for the first phase of the rehabilitation in the amount of $772,736.

Water System Improvements As noted above, the existing system during "high demand periods" experiences negative pressures in the water system which can result in pipe collapse, the introduction of contaminated water into the system from cross-connections, and the inability to meet user demand. Such conditions are not acceptable in a public water system.

Improvement to all of the water and wastewater facilities infrastructure is necessary to foster economic growth and employment opportunities, as well as, to improved the quality of life in the City of Brawley.

Water Distribution System In Phase 1 this project will replace portions of the existing distribution system with polyvinyl chloride (PVC) pipe to provide corrosion free, higher pressure water distribution. The existing distribution system includes cast iron pipes that are as much as 65 years old. The local alkaline soils attack these pipes from the exterior and the alkaline water attacks them from within. The pipes have become corroded and/or have extensive encrustation on the interior due to the salt buildup. This causes negative pressures in the water system which can result in pipe collapse, the introduction of contaminated water into the system from cross-connections, and the inability to meet demands. The results are:

1. Inadequate water pressure to meet the peak demand. This is dangerous situation in times of high summer temperatures or a fire emergency.
2. Intrusion of contaminated water can be a public health issue with grave consequences and demands immediate capital improvement.
3. Corrosion of pipelines can cause surface cave-ins, a public safety concern.

This project will also provide safe, dependable treatment of wastewater and provide for future growth of the city. The present wastewater treatment plant has deficiencies that must be addressed. Due to the combined design of the wastewater and storm drain system, large volume flows during storms necessitates that wastewater receives only primary treatment prior to discharge. In recent years, two citations have been issued against the City of Brawley by the California Regional Water Quality Control Board (RWQCB), Colorado River Basin Region. Both citations resulted from the illegal discharge of raw sewage from the wastewater treatment system into the New River. The first citation, Administration Civil Liability Order No. 94-063, was issued on May 20, 1994 following the discharge of an estimated 1.93 million gallons of raw sewage into the New River. The second citation, Time Schedule Order No. 97-115, was issued on July 28, 1997 following the discharge of an estimated 36,000 gallons of raw sewage into the New River on June 25, 1997.

In addition, the RWQCB issued a Notice of Noncompliance on November 4, 1998 citing the City for discharging treated effluent to the New River in excess of the daily maximum allowed by the wastewater treatment plant permit. The New River flows northerly to the already polluted Salton Sea.

The existing and future discharge permits are as follows:

The Phase 1 certified project, expanding and upgrading the WWTP, will decrease the likelihood of discharging raw sewage into the New River and reduce disease transmission through casual contact with raw sewage. It will increase capacity so that the increased flows that occur during storms can receive both primary and secondary treatment prior to discharge. It will also permit discharge of wastewater effluent that has been treated to a higher degree than currently possible. The addition of disinfection to the process will further treat the effluent before discharge.

The wastewater collection system was established more than 70 years ago. Over 50% of the system is combined sanitary/storm sewer and during heavy rain storm events, portions of the system surcharge. The pipeline segments selected for replacement under Phase 1 are those that determined as undersized during dry weather conditions when tested in a sewer collection system model. These pipelines were identified as priority replacements by larger diameter pipelines to prevent future surcharging and eventual health threats to the community.

Without the water delivery system and wastewater treatment system projects, public health problems may plague the community, perpetuating the spread of disease, continued school absenteeism, increased medical expenses, and the lost productivity.

The proposed projects require an environmental assessment. The documents for the public projects were prepared as required under state and federal law by Mooney & Associates. Appendix 11 of the City of Brawley Water and Wastewater Master Plan, prepared by Mooney & Associates, dated May 20, 1999 contains the Environmental Assessment/Mitigated Negative Declaration, as well as copies of the biological and archaeological surveys reports, and a copy of the EPA Finding of No Significant Impact (FONSI).

EPA issued a FONSI for the proposed project on July 28, 1999. The document underwent a 30-day public comment period through August 26,1999 (see Appendix 11).

The Mitigation Measures identified by Mooney & Associates in the April 20, 1999 draft are as follows:

Archaeological evidence suggests that humans have intermittently occupied the Imperial Valley for at least 12,000 years. Camps were often established near surface water streams. Significant archaeological resources potentially occur along the undeveloped banks of the New River and on the terraces overlooking the river channel. There is little or no potential for archaeological resources on the valley floor due to the disruption of surface from intensive agriculture.

A record search was conducted for the City of Brawley in 1979 to determine if any cultural resources sites have been identified. The records search did not reveal any indication of archaeological resources in the City limits. A cultural resource sensitivity map was prepared by Imperial Valley College for the County of Imperial General Plan update. The New River corridor is one of the few areas shown as potentially having highly sensitive archaeological resources. The New River was used extensively by the Kamia, a historic Yuman group, as late as the mid-1800s. There is little or no potential for archaeological resources on the valley floor due to the disruption of surface from intensive agriculture.

A cultural resource survey of the proposed wastewater treatment facility site was conducted by Mooney & Associates archaeologists. The study area consists of the area within the existing WWTP boundary proposed for siting of two new primary clarifier tanks, per the Aerated Lagoon expansion recommendation. No archaeological resources were identified in the existing WWTP boundary. A records search with the Office of Historic Preservation (OHP), Southeast Information Center, Imperial Valley College Museum and literature review were conducted for the study area of the Wastewater Treatment Plant. Record search information revealed that, within the WWTP area, no previous archaeological surveys have been conducted, and that there are no known, recorded archaeological or historical resources within the study area boundary.

All of the Phase 1 pipeline improvements fall within existing street systems, and therefore, in areas that have previously been graded and paved. Potential impacts to cultural resources associated with the pipeline projects within existing roadways are not significant based on the disturbed nature of roadbeds and the small size of the pipelines to be installed.

Within the WWTP boundary, the majority of the acreage is developed. Most land forms have been graded, excavated and intensively modified. No cultural resources were determined to be on or in the vicinity of the project site. The complete Cultural Resources report is in Appendix B of the Environmental Assessment.

Biological Resources

In order to determine if the proposed action would have the potential to impact biological resources, a biological inventory of the WWTP site, surrounding lands, and access road was conducted. This report is included in this EA/MND as Appendix C. The purpose of this survey was: 1) to compile a list of plant and wildlife species that occur along the access road and within a one-acre area surrounding the proposed site; 2) to provide a report that could be used by the lead agencies to expedite project review; and 3) to provide recommendations to facilitate project actions in a manner that reduces the potential for directly or indirectly affecting wildlife and plants.

The most significant biological resources in the Brawley Planning Area are associated with the desert riparian and freshwater marsh habitats along the New River. The New River is not a wild or scenic river. A substantial portion of the Planning Area is devoted to crop production. Although not considered sensitive, agricultural and other disturbed areas can provide valuable habitat to certain animal species such as large mammals, birds and raptors because they provide foraging opportunities.

A variety of sensitive animal species occur in Imperial County. The majority of these sensitive species are birds that forage in agricultural fields. Three sensitive wildlife species were either observed or considered to be potentially present.

A group of white-faced ibis was noticed flying over the WWTP property several times. This species is a State Species of Concern and is a winter migrant to Imperial Valley. A northern Harrier, which is also a State Species of Concern, was also observed flying over the northern end of the property, however, no nests were observed on site. This species feeds on small mammals, so it would not be expected to utilize the WWTP property, except possibly as a nesting site. The Northern harrier typically nests in open grassy fields, and there are currently no undisturbed fields to accommodate their habitat.

The burrowing owl is a State Species of Concern which often uses the burrows of squirrels or other small mammals. No evidence of burrowing owls was noted, although the species is known to occur within the general vicinity of Brawley. No small mammal burrows were noted during the survey, indicating an absence of rodents from the site. Without the presence of their primary food source, the potential for the burrowing owl to utilize the WWTP site is very low.

Most of the WWTP is devoid of vegetation. Landscape material has been planted along the perimeter of the existing buildings. Offsite and to the north, the property had been recently disced as part of an agricultural operation. The offsite property to the west is primarily devoid of vegetation, except where it is adjacent to the New River. Although periodically cleared, this area is left fallow. The routine clearing of vegetation as part of the WWTP site maintenance and as part of the agricultural activities offsite has suppressed natural recruitment of native vegetation.

Implementation of the Brawley Water and Wastewater Master Plans will result in the construction of new pipeline and removal and replacement of existing pipeline. This development will primarily occur on land where existing roadway exists or on land previously disturbed by agricultural uses. The majority of the projects recommended by the Master Plan are pipeline replacement projects within paved roadways.

Most of these roadways are residential streets and are lined by trees and landscaping. Adoption of the Water and Wastewater Master Plans would result in no direct impacts to biological resources.

No impacts to biological resources will result from the pipeline replacement projects within the existing roadways. No impacts are expected to trees lining the roadways. All construction will be confined to public rights-of-way.

No threatened or endangered or sensitive plants, were observed on the WWTP expansion site and none are expected to occur within the project area. No wetlands or sensitive or critical habitats were found on site. A buffer zone of 50 feet from the New River would be included in the WWTP plans, therefore, there would be no impact to wetlands. Since there were no threatened, endangered or sensitive plants within the study area, there will be no impacts. Expansion of the WWTP would not impact the white-faced ibis or burrowing owl due to their low potential for utilizing the site. There is a potential to impact the northern harrier if it is nesting onsite during construction

Imperial County can be generally divided into three geomorphic provinces: the Peninsular Range, the Salton Trough, and the Mojave Desert. The Salton Trough underlays the majority of the County including the Brawley Planning Area, and is often referred to as the Salton Sink, Salton Basin, Cahuilla Basin and the Imperial Valley. The Brawley Planning Area is underlain by a relatively thin sequence of Quaternary-aged (1.6 million years before present) lake-bed deposits. The lake bed deposits rest on a thick sequence of Tertiary age (1.6 to 63 million years before present) and older marine and non-marine sediments and volcanic rocks. Alluvial deposits are found in the New River Channel. The topography of the Planning Area is nearly flat with the exception of the bluffs along the New River Channel.

The Salton Trough is bounded by the San Andreas Fault System on the east and the San Jacinto and Elsinore-Laguna Salada Fault Zones on the west. These fault zones mark the boundary between the North American and Pacific Plates. Ground shaking during an earthquake is the most significant seismic hazard in Brawley. The Imperial, Superstition Hills, and Superstition Faults are most likely to cause significant ground shaking in Brawley.

Alluvial soils occur in the New River channel. These lake-bed deposits consist primarily of porous and unconsolidated clay, silt, and sand with traces of gravel and salt deposits. Liquefaction may occur when loose, unconsolidated, saturated, sandy soils are subjected to ground vibrations during a seismic event. The sediments exposed in the relatively steep bluffs of the New River are susceptible to landsliding and other slope instability problems.

The proposed water treatment facilities, water distribution pipeline, wastewater treatment plant and wastewater collection system are within areas where the soils have been disturbed by previous grading. All improvements will take place on already developed grounds of the existing treatment facilities. Common geologic concerns in Imperial County include earthquakes. Soil specific concerns include rates of compaction/settlement, shrink/swell, and erosional characteristics.

Available geologic information about the proposed pipeline routes indicates that there are no geologic conditions present that would preclude development along any of the proposed pipeline alternate routes. Areas of geologic instability could generally be mitigated with standard engineering practices or avoided by selecting alternative pipeline alignments. The soil and rock along the proposed pipeline routes would generally be suitable for excavation and fill. The proposed action itself would not be constrained by geologic features and would not result in significant geology or soils impacts. The proposed improvements in the Water and Wastewater Master Plans would not require extensive grading or landform alteration. The disruption and covering of existing soils would not be significant.

Prior to implementation, each project shall be assessed by the City of Brawley for its structural stability during a geologic event and for the appropriate engineering design, given the soils and hydrologic conditions where located. The results of the investigations will be used in the final project design. No further mitigation measures are required.

All improvements will take place on already developed grounds of the existing treatment facilities. Common geologic concerns in Imperial County include earthquakes. Soil specific concerns include rates of compaction/settlement, shrink/swell, and erosional characteristics. There are no impacts to geology/soils from the Phase 1 Project improvements

Air quality has been monitored in Imperial County since 1976. Particulate matter (PM₁₀) is monitored in Brawley and both PM₁₀ levels and ozone are monitored in El Centro. Ozone and PM levels exceed state standards in Brawley and the City is a non-attainment district for both. The Imperial County Air Pollution Control District (APCD) has prepared a plan to reduce ozone-forming emissions and attain state ozone standards. The APCD Air Quality Attainment Plan was prepared in 1991. The following strategies are included in the APCD Air Quality Attainment Plan: use of mixed land use to reduce reliance on the automobile; balancing jobs and housing by providing employment near residential areas; and communication, coordination and monitoring to review and implement land use management programs.

The urbanized portion of the Brawley Planning Area is surrounded by land used for agricultural production. Urban uses adjacent to or downwind of agricultural areas are occasionally subject to unpleasant odors and airborne pesticides

Adoption of the Water and Wastewater Master Plans would not directly impact air quality in Brawley. There are no sources of potential long term air impacts associated with the, implementation of recommendations, will however planned construction activities, could potentially result in short-term, construction-related impacts. The principal sources of potential air quality impacts associated with the proposed project are primarily associated with the construction effort, and include the following:

• Exhaust emissions from construction equipment;
• Fugitive dust from earthmoving operations;
• Fugitive dust from vehicles on paved and unpaved roads;
• Exhaust emissions from vehicles delayed by project related traffic control; and,
• Gaseous and particulate emissions from vehicles used by construction workers for commuting.

The California Air Resources Board (ARB) estimates that each acre under construction generates about eight pounds of fugitive dust per day. While no long-term air quality impacts would result from future pipeline operations, the operation of wastewater treatment facilities could result in treatment process emissions and odors. Long-term air quality impacts and corresponding mitigation measures will be assessed by the City of Brawley prior to implementation of Plan recommendations

3. Impacts of Proposed Phase 1 Project Improvements

The principal sources of potential air quality impacts associated with the proposed project are primarily associated with the construction effort, and include the following:

• Exhaust emissions from construction equipment;
• Fugitive dust from earthmoving operations;
• Fugitive dust from vehicles on paved and unpaved roads;
• Exhaust emissions from vehicles delayed by project related traffic control; and,
• Gaseous and particulate emissions from vehicles used by construction workers for commuting.

Odor from treatment facilities is always a primary public concern. As is true of all wastewater treatment facilities, the operations at the City-operated plant involve occasional emissions of objectional odors during either the treatment process or equipment failure. The improved treatment facilities should reduce current levels of odors, which are not considered to be significant. There are no sensitive receptors in the project areas and no significant air quality or odor impacts are expected

Dust control measures are required by Air Pollution Control District rules. Measures such as frequent watering, paving of access roadways, and periodic street washing in construction areas can reduce the dust generation rate by approximately 50 percent.

Although the production and emission of odors resulting from wastewater treatment processes cannot be prevented entirely, the impact of odors from the proposed improvements would be minimized in the same manner as odors are currently limited at the treatment facility. Specifically, the City shall continue to limit odors by:

• Providing the capability to adequately aerate and oxygenate treated wastewater.
• Providing reliable equipment and incorporating redundant features, such as back-up pumps and stand-by generators, into project design to ensure emergency back-up capacity in the event of mechanical or system failure.
• Continuing present odor control programs which involve ventilation of structures, covered structures, the use of masking agents, the use of non-odor-causing chemical treatments, aeration and aerobic digestion of wastewater, and continued surveillance and maintenance of equipment to minimize mechanical failure or breakdown.
• Sensitive receptors will be identified prior to construction of improvement projects and air quality mitigation measures implemented where significant impacts will occur.

Emission and odor control facilities will be incorporated into the engineering design of treatment plant expansions.

Surface Water The New River is the only natural surface water feature in Brawley. The New River presently flows into the Imperial Valley from Mexico with a significantly high waste load. The New River is subjected to pollution from raw and partially treated sewage and industrial waste from Mexicali, Mexico. As the river circulates through Imperial County, the flow dramatically increases as the result of drainage from the agricultural lands.

Groundwater Brawley is located in the Imperial hydrographic subunit. Groundwater quality in the region is generally poor, although isolated aquifers of good quality groundwater do occur. The poor groundwater quality is attributable to infiltration of agricultural runoff, and the presence of subsurface salt episodes of flooding, evaporation and subsequent deposition. Groundwater of the Imperial hydrographic subunit is generally unsuitable for domestic consumption under federal and state drinking water standards

The proposed action itself would not impact water resources. Implementation of the Master Plans however, could result in indirect impacts to water quality. The project would have a beneficial impact by improving effluent levels produced by an improved wastewater treatment facility. Additionally, local water supply will be benefited by increased water levels from improvements to pipeline. Pipe replacement will eliminate the extensive encrustation on the pipe interior, which will increase pressure levels and give greater reliability for peak hour and fire flows

Replacement of water and wastewater pipeline and the expansion of the Wastewater Treatment Plant would have a beneficial impact to water quality in Brawley. Replaced pipeline will provide more efficient and reliable water distribution throughout the city. An improved wastewater treatment facility will reduce effluent levels and therefore no significant negative impact is associated with the proposed action.

No mitigation measures are required for pipeline replacement projects within existing roadways. Standard construction site erosion control measures should be required for the pipeline and wastewater treatment plant expansion projects.

Several environmental conditions pose potential threats to public health and safety in Brawley. These conditions include seismic and other geologic hazards, flooding hazards, hazardous materials, fire and airport operations.

Flooding The New River occasionally floods during intense precipitation events. Flooding is presently not considered hazardous in the Planning Area because little development occurs in the flood channel and the elevation of the channel is substantially lower than the valley floor.

Hazardous Materials Accidents can occur during the use, storage, transport and disposal of hazardous materials and result in environmental contamination and threaten public health. Hazardous materials are used at industrial and commercial operations, farms and businesses related to agricultural production, the airport, and Union Pacific Railroad, including chemicals used at Wastewater Treatment Facilities.

The City shall continue to use the standard safety practices with the proposed action, and no significant impacts to health and safety will occur. There will be no development in a floodplain, thus there will be no impacts due to flooding.

As with all treatment facilities, the existing wastewater treatment facility is enclosed by fencing and is clearly marked as a restricted area. Signs are posted on the fencing that prohibit unauthorized entry and warn that wastewater should not be consumed. Standard treatment practices are maintained to insure that all facilities are in compliance with County, State and Federal treatment and discharge regulations

For pipeline projects, all necessary barricades, traffic cones, warning signs, lights and other safety devices shall be provided.

Noise is generally defined as annoying, harmful, or unwanted sound. Community noise levels are measured in terms of intensity and duration. Intensity is average over a 24-hour period and is expressed in decibels (dB) on a logarithmic scale. Ambient noise levels in populated areas are typically measured using a weighted average of the sound energy level during specified measurement period.

Existing noise in Brawley is primarily the result of transportation activities. Three State Routes converge in Brawley and the associated car and truck traffic generates substantial noise during both the day and night. The airport and railroad also produces noise. Other sources in addition to transportation activities include commercial, industrial and agricultural operations. The existing water treatment facility and wastewater treatment plant are not located near any sensitive noise receptors.

2. Impacts of Proposed Action

Adoption of the Water and Wastewater Master Plans would not directly increase noise levels in Brawley. Implementation of these Plans would typically require construction activity, which would increase daytime noise levels in adjacent areas. The duration of the construction-related noise would depend on the nature of the project. For example, pipeline construction projects can result in intense, intermittent noise during the construction period.

Noise generated by construction activities for the proposed program would be a short-term adverse impact, but would generally not be significant. The noise levels would be typical of construction and improvement projects that often occur in urban areas. The increase in noise would be experienced for a limited time period, and phased over a 20-year period, therefore, the potential impact will not be significant.

Construction noise would most severely affect noise-sensitive residential, recreational and educational land uses that are near the construction sites, however, the project is not located near any sensitive noise receptors.

The following measures are suggested to reduce short-term, adverse noise impacts that would result from the Wastewater Treatment Plant Expansion project:

• Select the most quiet type of equipment possible, and install factory-standard silencing equipment on power-operated equipment.
• Turn off idling equipment;
• Schedule the noisiest operations to coincide with the time of highest ambient noise levels.

Any significant noise impacts would be avoided or mitigated by compliance with the City Noise Ordinance.

The City of Brawley is located in a broad desert that has been transformed into productive agricultural lands by imported irrigation water. The City of Brawley presently contains a variety of residential uses. Non-residential uses include commercial, office, industrial, school, civic and other public uses. Approximately 5.2 percent of the Planning Area is occupied by non-residential uses. Land uses along the pipeline routes include commercial, residential, etc.

State planning law requires consistency between a city’s general plan and zoning ordinances. The land use designations have been revised in the updated Brawley General Plan. The Zoning Ordinance serves as the primary implementation tool for the Land Use Element policies and programs.

Adoption of the Water and Wastewater Master Plans would not directly impact land use in Brawley. According to the General Plan, as Brawley matures, additional demands will be placed on public facilities such as Water and Wastewater. Implementation of recommendations would be in accordance with the General Plan Land Use Element to alleviate infrastructure systems not currently capable of accommodating project growth areas, as well as replacement of aging portions of the system in order to maintain quality services. Recommendations in the Water and Wastewater Master Plans shall be implemented in current Public Facility Designated areas.

Short-term land use impacts caused by construction of the proposed pipelines would result from street closures, truck traffic, and disruption to local traffic using the street system to reach residences and businesses. Residential and commercial areas would also be disrupted by the noise from construction equipment.

All pipeline replacement projects within Phase 1 will occur in existing streets, and will not conflict with any land uses. The proposed WWTP expansion project will not substantially change the overall land use character of the area, since the project site is currently being used as the existing wastewater treatment plant. There are no residential, commercial or industrial land uses in the area.

There are no significant impacts, and therefore no mitigation measures are required.

The implementation of the proposed Water and Wastewater Master Plans occurs within existing developed areas, and will not impact either Prime Farmland or Farmland of Statewide Importance. Construction of the proposed pipelines would have minimal direct impacts to agricultural areas. Short-term crop damage from construction generated dust in immediately adjacent areas is not expected to be significant.

The Proposed Action takes place within the existing Wastewater Treatment Plant area and streets and therefore, there are no impacts to agriculture associated with the project.

There are no impacts associated with the Proposed Action, and therefore no mitigation measures are required.

Where the proposed pipelines would be placed in open trenches within existing roadway right-of-ways, there would be short-term traffic impacts associated with construction. These impacts would include disruption to through traffic as a result of street and lane closures; truck traffic from construction; and movement of equipment operators, carpenters, laborers and other construction and supervisory personnel who will typically arrive at 7:00 a.m. and depart at 4:00 p.m. These impacts would be limited to those portions of the project where the pipeline is placed in paved roadways. Pipeline construction will occur in several existing roads throughout the City, and road closures and traffic diversions may occur. However, based on the relatively low existing and project related traffic, both during construction and following completion of the proposed pipeline replacement and wastewater treatment facility, traffic is not considered to be a significant impact with respect to total trips. Figure 7.x shows the streets that will be affected by the proposed project.

There will be short-term impacts to traffic during the construction period of the Phase 1 project improvements, including increased construction-related traffic from, the movement of materials and equipment as well as the construction personnel who will typically arrive at 7:00 a.m. and depart at 4:00 p.m. The traffic generated by these activities will be short-term and insignificant since there are relatively few roads surrounding the project site that will be affected. The following streets will be impacted by construction-related traffic:

The California Environmental Quality Act (CEQA) defines growth inducement to include projects which remove obstacles to growth and accommodate additional population or construction, such as expansion of public service facilities. While the proposed project would entail the expansions of wastewater plant improvements and new pipeline, these proposed improvements are designed to provide an adequate supply of potable water and sewer service in accordance with the City’s established goals for growth and economic development, and to meet state and federal water quality standards and, therefore, are not considered growth inducing.

Adoption and implementation of the Brawley Water and Wastewater Master Plans will not cause growth but the Master Plans will enable the provision of water and sewer service to future development. The objective of the Brawley Water and Wastewater Master Plans is to anticipate the projected growth and provide a framework to manage new development projects and minimize local and regional environmental impacts.

The Brawley Water and Wastewater Master Plans, which meet state and federal standards, are not considered growth inducing since the Brawley General Plan states the City’s desire to accommodate growth in designated areas while limiting development in areas of environmental sensitivity or where public safety hazards exist.

Phase 1 Project Improvement projects would not be considered growth inducing, as they are in response to existing conditions. The Water and Wastewater Master Plans show that existing water distribution pipeline and wastewater collection pipeline need replacement to meet existing water and wastewater demands.

The proposed project would entail construction of wastewater treatment plant improvements; however, these proposed improvements are not designed to provide wastewater treatment in excess of the City’s established goals for growth and economic development. Instead, the proposed project seeks to improve the quality of the City’s water so that it meets state and federal standards.

No mitigation measures are required

NEPA 1508.7 states that: A cumulative impact is the impact on the environment which results from the incremental impact of the action when added to other past, present, and reasonably foreseeable future actions regardless of what agency (Federal or non-Federal) or person undertakes such other actions. Cumulative impacts can result from individually minor, but collectively significant, actions taking place over a period of time.

Cumulative impacts have been analyzed for all subjects above. Impacts, which include the wastewater treatment plant expansion, an upgrade to the wastewater collection system, upgrades to the water distribution system and future expansion of the water treatment plant. The implementation of the Master Plans would contribute to the degradation of regional air quality and traffic conditions. These impacts would result from the proposed construction activities at the treatment facility and proposed installation of distribution pipelines along area roadways. Traffic control plans will reduce traffic congestion in roadways used for the location of distribution piping and air quality control measures will reduce impacts during construction. Based on the short-term nature of the impacts, there are no significant impacts based upon the projects recommended by the Master Plans.

There are no significant unavoidable or adverse effects due to the Water and Wastewater Master Plans.

Adoption of the Water and Wastewater Master Plans and Phase 1 project improvements would be a beneficial environmental use. Implementation of these master plans would require construction of pipelines and the expansion of water and wastewater treatment facilities. The majority of these system improvements would occur in roadways and previously disturbed land. Implementation of Plan recommendations would not restrict beneficial land uses. The Wastewater Master Plan would provide a long-term facilities and services plan to guide expansion and improvements. Adoption of the Water and Wastewater Master Plans would allow a greater number of property owners to use the water and sewer systems. This action would alleviate some of the groundwater problems and effluent levels, as discussed in the section on Impacts of Proposed Action to Hydrology/Water Quality

Adoption of the Water and Wastewater Master Plans is an administrative action. The action would not require use of nonrenewable resources. Development would result in a long-term and possibly irreversible commitment of energy and other resources connected with site development and operations. Build-out of the proposed action represents a long-term commitment for a variety of resources, thus increasing energy demands related to project construction, lighting, heating and transportation of people to and from the site. Construction projects including Phase 1 improvements would require commitment of additional natural resources including lumber and forest products, sand and gravel, asphalt, petrochemicals, and other construction materials

The approving agency for the environmental laws and regulations is the USEPA. The contact person and address are:

The NPDES Permit Order Number 95-014, NPDES Number CA104523 (Appendix 12), presently in effect for the City of Brawley’s Wastewater Treatment Plant expires March 29, 2000, five years from effective date. The City of Brawley is in the Colorado River Basin Region of the California Regional Water Quality Control Board. The contact address is:

Executive Director

California Regional Water Quality Control Board

Colorado River Basin Region

73-720 Fred Waring Drive, Suite 100

Palm Desert, CA 92260

The study area includes the incorporated City of Brawley as well as the surrounding area that is within the City's current Sphere of Influence, as described in the City's 1995 adopted General Plan. The total area covers 15,469 acres or 24.2 square miles. In addition to the incorporated City, this area includes the proposed Luckey Ranch Development and the special study areas such as North Airport, East Bend Road, Southeast Malan, East Highway 86, Downtown, and West Airport

Both the existing and future conditions have been analyzed by Pountney for average annual demand, peak hour, and maximum day plus various fire conditions. All of the system modeling computer runs were made in the Extended Period Simulation mode. For the peak hour runs, the system was analyzed for one hour. For the Average Annual Day (AAD) and Maximum Day plus fire (MDF) runs, the system was analyzed for 24 hours to verify how the pumps and tanks operate. In the 24-hour runs, a typical hourly demand chart was input into the model to simulate varying demands throughout an average day. (The hourly chart is per The American Water Works Association (AWWA) Manual M3 1, Distribution System Requirements for Fire Protection). Based on this chart, the highest demands during a 24-hour period occur at 8:00 PM and have a, factor of 1.6, while the lowest demands occur between 2:00 AM and 5:00 AM, with a 0.5 factor.

For both the existing and future conditions, demands were calculated for individual land use areas and then the demand was separated between modeled junctions that were located within that land use area. These demands were then inserted into the computer model (See Table 4-0).

Since the certification is for the Phase 1 rehabilitation of existing conditions, only the existing conditions specifications will be presented.

(1) Taken from City of San Diego Water & Sewer Design Guide, September 8, 1994

(2) Peak Hour Peaking Factor was taken from City of San Diego graph with 7.4 MGD AAD and 1.6 Maximum Day Peak Factor

(3) Rate has been calculated based on the AAD of 7.4 MGD

The existing water system model, which includes the existing Water Treatment Plant (WTP) pump station, was calibrated by comparing some of the pressures recorded during the City's fire hydrant testing with the pressures developed by the model. The Hazen Williams roughness coefficient C and/or the pipe diameter in areas in which the pressures did not match closely was then adjusted. A C factor of 100 (typical for cast iron pipe over 20 years old) was used for all cast iron pipes and C factors of 140 and 150 were used for the AC and PVC pipes, respectively. With these factors, the majority of the recorded pressures that were checked were within 6 psi of the modeled pressure.

Of the areas checked, there were only two that did not fall within the 6 psi range. One was at 245 Magnolia and required that pipe # P-602 be modeled as a 2" diameter pipe. (A 2" diameter is the smallest pipe that the computer can model.) The other, on Vine Street adjacent to the Miguel Hildago Grammar School, had a recorded pressure of 28 psi at one hydrant and roughly one half block away another hydrant had a recorded pressure of 44 psi. The modeled pressure at both locations was 54 psi. The cast iron pipes in the vicinity of the low pressures were changed to 2" diameter pipes but the model still could not obtain the 28 psi and 44 psi. As the conditions under which the fire hydrant pressures were recorded are unknown (i.e., time of day, peak flow, max day), the 44 psi is deemed to be within an acceptable range of the modeled pressure. As for the 28 psi, it is possible the fire hydrant and/or the pipe in the vicinity of the fire hydrant may be plugged.

The existing water system analyses were made using the calibrated existing distribution piping and the 1999 water treatment pumps and reservoirs. The following presents a discussion of each of the computer runs along with minimum system pressures (excluding nodes on the suction and discharge sides of the pump stations). Maximum pressures are only given for the AAD runs, as it is a pumped system and the maximum pressure does not vary significantly.

Existing Average Annual Demand: This is the existing AAD run, which includes a total 7.5 MGD demand on the system.

Minimum Pressures:

EA-16 55.5 psi

JO-11 55.6 psi

EA-15 55.6 psi

(These junctions are on Eastern Avenue just south of the Airport.)

Maximum Pressures:

WTP-3 71.8 psi

WTP-4 71.8 psi

(These junctions are at the 1999 Water Treatment Plant.)

Existing Peak Hour Demand: This is the existing PH run, which includes a total 21.7 MGD demand on the system.

Minimum Pressures:

EA-16 42.1 psi

JO-11 42.1 psi

EA-15 42.1 psi

(These junctions are on Eastern Avenue and Duarte Street just south of the Airport.)

Existing Maximum Day Plus Fire at Junction KB-3: This is the existing MDF run, which includes a 6,000 gpm industrial fire at Junction KB-3, as well as a maximum day demand of 12.0 MGD. (The peaking factor is 1.6.) Junction KB-3 is the Brawley Municipal Airport. (Several runs were made simulating fires at various junctions and this location had some of the worst pressures.)

Pressures shown are at 8:00 PM, when demands are the highest.

Minimum Pressures:

KB-3 -337.1 psi (negative)

KB-2 -119.5 psi (negative)

KB-I - 53.3 psi

(These junctions are in Ken Bemis Drive at the Airport.)

Existing Maximum Day Plus Fire at Junction EA-1 6: This is the existing MDF run, which includes a 6,000 gpm industrial fire at Junction EA-16, as well as a maximum day demand of 12.0 MGD. (The peaking factor is 1.6.) (Several runs were made simulating fires at various junctions and this location had some of the worst pressures.) Pressures shown are at 8:00 PM, when demands are the highest.

Minimum Pressures:

EA 16 - 1,069 psi (negative)

JO-11 - 736 psi (negative)

EA-15 - 736 psi (negative)

(These junctions are on Eastern Avenue and Duarte Street, just south of the Airport.)

The existence of negative pressures in a water system can result in pipe collapse, the introduction of contaminated water into the system from cross-connections, and the inability to meet user demands. Such conditions are not acceptable in a public water system. To eliminate these conditions, modifications to the system were made, and the model was rerun including the AAD, MDF, and Peak Hour (PH) conditions. The pipe modifications are shown in Appendix 13 and generally, include the following:

• Replace all existing 4", 6", and 8" cast iron pipe with 8" PVC minimum. All larger diameter cast iron pipes should be replaced with PVC pipe of the same size. The existing cast iron pipe is as much as 65 years old and has shown signs of significant tuberculation, which has decreased the capacity of the pipes and increased headloss through the pipe. The 4" and 6" pipes are replaced with 8" minimum, as 4" and 6" pipes do not typically have the capacity to provide adequate fire flows and velocities. It is typical to use 8" minimum water pipes except in unlooped, short cul-de-sacs.
• Replace all cast iron pipe which lies in a commercial or industrial zone with 12" PVC. To provide adequate fire flows and veloc