Wastewater Treatment Facility Overview

Welcome

Welcome to the City of Dripping Springs’ website dedicated to the proposed expansion of its wastewater treatment facility. Within this site, you will find information about the project need, as well as project details and the research that is guiding the process.

This is an incredibly complex and technical topic; we hope this site serves as a helpful resource for you. As part of its planning efforts, the City spent the last several years conducting research, which is available to you on this site, including a Preliminary Engineering Report and a Direct Potable Reuse (DPR) Feasibility Study.

Additionally, you will find a glossary of related terms, a fact sheet and frequently-asked-questions. This site will also house project updates and news as the City moves forward in the planning and implementation process.

We welcome your feedback, as well as your questions. Please, contact us at wastewater@cityofdrippingsprings.com for more information. City staff is also happy to schedule a meeting with you to discuss the wastewater-expansion issue in greater detail, if you are interested.

Project Need

Hays County has experienced tremendous growth over the last 10 years with its population increasing by more than 60 percent. The Dripping Springs area has seen significant growth as well, with no signs of slowing down. Numerous developments are already underway in the area with more subdivision projects approved and contemplated. Several developments are underway including The Retreat at Dripping Springs, Texas Heritage Village, the proposed Heritage Public Improvement District (PID), Founders Ridge, Arrowhead Ranch and Caliterra, along with several individual commercial projects in and around the city limits.

To address this growth, there must be sufficient water and wastewater infrastructure in place. Generally, there are two ways that infrastructure can be provided. One, each individual subdivision could develop its own sewage collection and treatment system and obtain a permit for effluent disposal. Or, a regional collection and treatment system could be developed.

Because of this, a significant concern exists about the lack of wastewater capacity to serve the growing population and how it could negatively impact Dripping Springs for years to come in the City’s ability to meet the needs of residents and businesses. In fact, based on current volumes, it is likely the City will run out of capacity very soon.

The City Council took the proactive step to meet the needs of the community by initiating a comprehensive study in 2013 evaluating current and future wastewater infrastructure demand. This action was supported by the Dripping Springs Economic Development Committee, which is comprised of respected business and community leaders.

Project Details

The City of Dripping Springs is moving forward with plans to expand its existing wastewater treatment facility to provide necessary additional capacity. The current South Regional Wastewater Collection, Treatment and Disposal Facility serves the greater Dripping Springs area and provides service to more than 270 residential and commercial customers. It utilizes subsurface drip irrigation for effluent disposal.

Over the last few years, the City has received numerous sewer service requests. In response to these requests, the City filed an amendment in February 2014 with the Texas Commission on Environmental Quality (TCEQ) to increase its TLAP-permitted capacity from 162,500 GPD to 348,500 GPD; it was approved and then issued in November 2015. This permit amendment includes construction of a treated effluent line to a new subdivision and permits additional surface irrigation area and an effluent holding pond within that development. All of that pending capacity is already allocated for future residential developments and commercial customers, while the City continues to receive additional requests for service.

As part of its research, the City carefully examined its options for wastewater treatment and disposal. The two most common are discharge to waters through a Texas Pollutant Discharge Elimination System (TPDES) permit or land application under a TLAP permit. The cost of a new treatment plant with effluent discharge has been estimated to be $9 million, while the cost of a new treatment plant with effluent storage and land application has been estimated to be $18 million. Additionally, as the City and its surrounding subdivisions continue to grow, it will be more difficult to acquire tracts of land suitable for spray irrigation.

The City Council believes the long-term solution to its wastewater issue is to obtain a TPDES discharge permit and utilize Beneficial Reuse immediately and Direct Potable Reuse in the future (DPR) in an effort to reduce the volume of treated effluent that would be discharged. Beneficial Reuse would treat and reuse treated effluent to supplement treated surface water and groundwater currently used for irrigation at city parks and other areas around Dripping Springs to supplement drinking water supply, while reducing the need for disposal of treated wastewater. The City plans to move forward with as much Beneficial Reuse as possible, which is commonly utilized for irrigation of road right-of-way and medians, greenbelts, parks, open areas and sports fields. To that end, the City has an agreement with one mixed-use development, and is in active negotiations with others, to accept treated effluent for reuse at their respective developments.

A next step in delivering on a long-term solution, the City filed for a TPDES discharge permit, allowing for the expansion of its current wastewater treatment system to a permitted future capacity of 995,000 GPD. This will include wastewater treatment expansion and improvements to treat the wastewater to a more stringent level, and will include a treated effluent pump station to deliver the reclaimed water to “Chapter 210” reuse customers throughout the area. The City believes that most, if not all, of the effluent can be beneficially reused. However, even with Beneficial Reuse (also known as Chapter 210 reuse), there will be times where the City routes treated effluent to the discharge point at Walnut Springs Creek.

Project Quick Facts

• Hays County population has increased by 60 percent in the last 10 years.

• The current South Regional Wastewater Collection, Treatment and Disposal Facility, which serves area residents and businesses, operates under a TLAP permit, and utilizes subsurface drip irrigation for effluent disposal.

• The facility provides service to more than 270 residential and commercial customers in the greater Dripping Springs area. Its current average daily flow of treated wastewater is approximately 75,000 gallons per day (GPD).

• The City filed for an amendment to its TLAP permit with the Texas Commission on Environmental Quality (TCEQ) to increase permitted capacity from 162,500 GPD to 348,500 GPD. That amendment was recently authorized.

• The City filed an application for a TPDES discharge permit, allowing for the expansion of its current wastewater treatment system to a permitted capacity of 995,000 GPD.

• Of the permitted capacity of 995,000 gallons per day, the City plans to use a portion of the treated effluent to irrigate City-owned land, including parks and medians. In addition, it has entered into agreements with developers in the area to receive close to 500,000 gallons per day for beneficial reuse within their developments, bringing the current total to more than 600,000 gallons per day committed to reuse purposes.

• The estimated cost of the proposed wastewater facility expansion with discharge is approximately $9 million.

• By comparison, the estimated cost of the proposed wastewater facility expansion with land application is approximately $18 million.

 

Project Milestones

The following timeline is intended to serve as a chronology of action taken by City to determine the appropriate path forward in addressing its growing wastewater needs.

2003 – The City of Dripping Springs acquired approximately 40 acres of land for a new wastewater treatment and disposal facility. The Crenshaw family donated the land to the City.

2003 – Nov. 2008 – During this time, permitting, design and construction of the City’s current wastewater collection, treatment and disposal facilities were completed. The treatment plant, effluent holding tank, operations building and subsurface drip irrigation fields were constructed on these 40 acres; the full facility went into operation in November 2008. The intent of the new system was to accommodate current residents and businesses, plan for future growth and move the greater downtown area off of failing septic systems.

2008 – 2009 – The City of Dripping Springs applied for and was awarded a Community Development Block Grant by the federal government and administered by the State of Texas. As a result, 82 residences in the North Forty subdivision were provided wastewater service. The grant paid for the associated impact fees and construction costs to connect the homes to the City's wastewater system, yielding an approximate cost-savings of nearly $800,000.00 for these residents in wastewater connection fees, alone.

Feb. 2013 – Dripping Springs City Council authorized CMA Engineering to conduct a comprehensive study evaluating its wastewater capacity and potential infrastructure needs. The study examined two critical issues: 1) Meeting the wastewater needs of existing residents and businesses; and 2) Estimating growth and managing the commercial and residential developments planned for the area. CMA’s analysis looked at the issue through a variety of lenses – financial, environmental, sustainability and community impact. It also looked at a number of potential disposal scenarios, including land application, spray irrigation, drip irrigation (the City’s current disposal method), discharge and Beneficial Reuse.

Aug. 2013 – The City identified an interim solution to its current wastewater need through a partnership with a mixed-use developer.

Jan. 2015 – The City initiated an outreach effort aimed at communicating the wastewater capacity need facing the area and the problem it is working to address.

Feb. 2015 – June 2015 – The City commissioned a study of Direct Potable Reuse (DPR), in partnership with local landowner Gary Keller, aimed at evaluating that option; Carollo Engineers was tasked with the feasibility study. The idea behind DPR would be to treat and reuse wastewater to supplement the City’s drinking water supply, while reducing its need for disposal of treated wastewater. The study also evaluated the feasibility of land application for a 500,000 GPD facility. The City Council expressed its support of DPR as a long-term solution to both its water and wastewater issues. To demonstrate the City’s commitment to DPR in the future, the proposed plant expansion (995,000 gallons per day) includes as a first phase the conversion of the existing wastewater treatment plant to a Biological Nutrient Removal facility, one of the most advanced treatment facilities available. Additionally, the City and the Dripping Springs Water Supply Corporation are now in active discussions regarding the feasibility of a DPR project.

Oct. 2015 – The City of Dripping Springs filed an application for a Texas Pollutant Discharge Elimination System (TPDES) permit with the Texas Commission on Environmental Quality (TCEQ). The ultimate wastewater capacity of this discharge permit application is 995,000 gallons per day.

Nov. 2015 – The City applied for and was issued an amendment to its current wastewater permit to increase its treatment and disposal capacity to 348,500 gallons per day; it is already allocated to future developments.

Dec. 2015 – The City announced an agreement with a mixed-use development in which the developer agreed to receive 118,000 gallons per day of treated wastewater from the City to use as Beneficial Reuse. The City is actively working to secure additional Beneficial Reuse agreements with other interested buyers in the area.

Jan. 2016 – The City of Dripping Springs and the Dripping Springs Water Supply Corporation entered into a non-binding letter of intent to explore a 500,000 GPD joint Direct Potable Reuse (DPR) project to serve the area.

Ongoing – The City has met with a wide variety of stakeholders over the last several years – landowners in the immediate and surrounding areas, developers, municipalities, including the City of Austin and county representatives, and a variety of other agencies, such as the TCEQ and LCRA. These meetings are ongoing today. Additionally, the wastewater issue has been discussed at numerous Dripping Springs City Council meetings, all of which were open the public.

Estimated Timeline for Additional Milestones

Late 2017 to Early 2018 – Texas Pollutant Discharge Elimination System (TPDES) permitted is issued.

Mid 2018 to Late 2018 – Wastewater treatment plant design completed.

Mid 2019 to Late 2019 – Wastewater treatment plant construction begins.

Late 2019 to Early 2020 – Wastewater treatment plant construction completed.

 

South Regional Wastewater System Expansion Study

The City conducted a thorough evaluation of its wastewater capacity and the challenges facing the area, led by local firm CMA Engineering. The study, the Preliminary Engineering Planning Report for the South Regional Wastewater Expansion, set out to help the City and its area residents better understand two critical issues – how to:

• Meet the wastewater needs of existing residents and businesses;
• Proactively plan for commercial and residential development moving into the area.

The analysis looked at the wastewater issue through a variety of lenses – environmental, financial, sustainability and impacts to stakeholders. It also looked at growth estimate scenarios, and a number of potential disposal scenarios, including spray irrigation, drip irrigation (the City’s current disposal method), discharge and Beneficial Reuse.

The full engineering report may be found here.

Direct Potable Reuse Feasibility Study

The City of Dripping Springs, in partnership with local landowner Gary Keller, hired Carollo Engineers to conduct a Direct Potable Reuse (DPR) feasibility study. The idea behind DPR is to treat and reuse wastewater to supplement the City’s drinking water supply, while reducing its need for disposal of treated wastewater. Though not yet widespread, DPR is being considered by several municipalities with water supply shortages.

The City Council expressed its support of DPR as a long-term solution to both its water and wastewater issues. As a direct result of this study, the City and the Dripping Springs Water Supply Corporation have signed a non-binding letter of intent to study and develop a scope for a potential feasibility of a 500,000-gallon-per-day DPR project.

To further demonstrate the City’s commitment to DPR in the future, the proposed plant expansion (995,000 gallons per day) includes as a first phase the conversion of the existing wastewater treatment plant to a Biological Nutrient Removal facility, one of the most advanced treatment facilities available. Note that even with DPR, a municipality would have to have and maintain either a TPDES or TLAP permit, since 100 percent of the effluent could not be used all of the time.

The full DPR feasibility study may be found here.

 

Frequently Asked Questions

What is the City of Dripping Springs’ South Regional Wastewater Collection, Treatment and Disposal Facility (Wastewater System)?
The South Regional Wastewater Collection, Treatment and Disposal Facility is currently a 162,500-gallon per-day (GPD) wastewater treatment facility that uses an activated sludge process to treat wastewater and subsurface drip irrigation for effluent disposal. It is located at 23127 West FM 150 and serves the greater Dripping Springs area by providing wastewater services to more than 270 residential and commercial customers.

Why did the City conduct a Wastewater System Study? Why does Dripping Springs need more wastewater capacity?
Hays County has experienced tremendous growth over the last 10 years with its population increasing by 60 percent. The Dripping Springs area has seen significant growth as well, with no indication of slowing down. Numerous developments are already underway in the area with more approved and others contemplated, especially by major employers. For those reasons, there must be sufficient infrastructure in place.

There is a growing concern that lack of wastewater capacity will negatively impact Dripping Springs for years to come in its ability to meet the needs of existing residents and businesses. In fact, based on current volumes the City is expected to run out of capacity in 2017. The City is taking a proactive and responsible approach in meeting the needs of prospective developments and protecting citizens in determining how the area will grow in a sensible manner. A substantial part of this effort involved the evaluation of current and future infrastructure needs, including wastewater capacity.

What is the Wastewater System Preliminary Engineering Planning Report (Study)?
The Wastewater System Preliminary Engineering Planning Report is a comprehensive analysis of the City’s existing wastewater treatment facility. The study evaluated current wastewater flows and calculated future projections, as well as anticipated infrastructure needs based on population growth. The study also helped identify costs associated with expanding the collection and treatment system.

Who conducted the Study for the City?
The study was a project authorized by the City of Dripping Springs. We hired local firm CMA Engineering, Inc. to lead the research effort. CMA Engineering is an established Texas-based engineering firm that specializes in providing environmental and civil engineering services to municipalities. The company is familiar with the City’s existing facilities and understands the issues relative to the sensitive Edward’s Aquifer region.

What did the City do with the results of the Study?
The study assisted the City in selecting and implementing a long-term plan to expand its system to provide wastewater services to current and future residents and development.

What is the schedule for the proposed expansion?
It is anticipated that the wastewater expansion permitting and construction process will take approximately three to five years. The City filed its permit application with the TCEQ in October 2015.

Has the City selected a site for the proposed expansion? Why was it selected?
The current facility will remain in its same location on FM 150. The proposed discharge point would be located near the intersection of RR 12 and FM 150. The discharge point would be into Walnut Springs Creek, approximately one-half mile from its confluence with Onion Creek.

How much will the proposed wastewater system expansion cost the City of Dripping Springs?
The estimated cost of the proposed wastewater facility expansion with discharge is approximately $9 million.

What is treated effluent discharge?
Treated effluent discharge is the release or disposal of treated effluent into or adjacent to any water in the state. A TPDES permit to discharge must be approved by the Texas Commission on Environmental Quality (TCEQ).

Did the City explore other disposal options? Why does it believe seeking a discharge permit is the best option?
The City of Dripping Springs examined and evaluated both methods of disposal – land application and discharge – through several lenses, including environmental, financial, long-term maintenance, impacts to community and ability to scale with community need. Both the CMA and Carollo studies evaluated land application as a method of disposal. Very few land-application permits exist in the state to support wastewater treatment plants greater than 500,000 gallons per day, which the Dripping Springs’ plant would be. That is due to the amount of land and effluent storage required and the costs associated with acquisition and ongoing maintenance. More importantly, the discharge option paves the way to achieve the City’s long-term goals of Direct Potable Reuse and Beneficial Reuse.

Will the City discharge into Onion Creek?
The City proposes to discharge into Walnut Springs Creek only as necessary; this location is approximately one-half mile from Onion Creek. However, the City prefers not to discharge, as it believes treated effluent is a significant resource, and for that reason, is focused on Beneficial Reuse. We are actively seeking Beneficial Reuse customers in the area and have reached an agreement with one subdivision in which the development will receive 118,000 gallons per day of treated effluent that will be reused for irrigation purposes.

Would future Dripping Springs City Council be required to pursue Beneficial Reuse?
Future City Councils would not be bound by law to pursue Beneficial Reuse contracts and other opportunities. However, significant infrastructure is already in the ground today to support Beneficial Reuse, which is also creating a substantial revenue stream for the City to help address other critical needs for citizens.

Glossary of Terms

The topic of wastewater can be extremely technical and complex. With that in mind, please find below a glossary of related terms that may prove helpful in the ongoing discussion around the City’s proposed wastewater-expansion efforts.

• Algae – Aquatic plants that occur naturally and are normal components of a healthy ecosystem. They contain chlorophyll that live floating or suspended in water. They also may be attached to structures, rocks or other submerged surfaces. Excess algal growths can impart tastes and odors to potable water. Algae produce oxygen during sunlight hours and use oxygen during the night hours. Their biological activities appreciably affect the pH, alkalinity and dissolved oxygen of the water.

• Algal Bloom – Sudden, massive growths of microscopic and macroscopic plant life, such as green or blue-green algae, which can, under the proper conditions, develop in lakes, reservoirs and ponds.

• Beneficial Reuse/Chapter 210/Reclaimed Water – Former wastewater that is treated to remove solids and impurities, and used in sustainable landscaping irrigation, construction water used for dust control and re-vegetation; to recharge groundwater aquifers, and to meet commercial and industrial water needs.

• Direct Potable Reuse (DPR) – The use of reclaimed water that is piped directly from a wastewater treatment facility to a potable drinking water treatment and distribution system.

• Discharge – The release or disposal of treated effluent into or adjacent to any waterway in the state. Must be approved and permitted by the Texas Commission on Environmental Quality.

• Disposal – Once wastewater has been treated, it is re-introduced into the environment. Methods for disposing of treated effluent include drip irrigation, spray irrigation, discharge and Beneficial Reuse.

• Drip Irrigation – In terms of wastewater disposal, treated effluent is released through a drip system located above or below the ground.

• Effluent – Treated wastewater; the final output flow of a wastewater treatment plant.

• Indirect Potable Reuse – The use of reclaimed water to augment drinking water supplies by discharging it to a water body, such as groundwater or surface water, which is subsequently treated for human consumption.

• Land Application – Treated effluent disposal method; options include surface irrigation, evaporation, drain fields or subsurface irrigation.

• Potable Water – Water that does not contain objectionable pollution, contamination, minerals or infective agents, has been disinfected, and is considered satisfactory for drinking.

• Purple Pipe – Pipe that carries reclaimed water that is not potable, but is clean enough for Beneficial Reuse.

• Raw Wastewater/Sewage – Wastewater treatment plant influent or wastewater before any treatment and disposal. It can consist of a community's used water and water-carried solids (municipal and industrial) or some amount of storm water, surface water and groundwater infiltration into a wastewater collection system.

• Reuse – The use of water or wastewater for various beneficial purposes.

• Runoff – That part of rain or other precipitation that runs off the surface of a drainage area and does not enter the soil or the sewer system as inflow.

• Spray Irrigation – Form of irrigation in which treated effluent is sprayed over vegetation and plants to provide them with water.

• Texas Commission on Environmental Quality (TCEQ) – The Texas Commission on Environmental Quality is the environmental agency for the State of Texas. The agency’s goal is clean air, clean water and the safe management of waste. Its operating groups include the Office of Air, the Office of Water, the Office of Waste and the Office of Compliance and Enforcement. The TCEQ issues permits for discharge and for land disposal of effluent.

• Texas Land Application Permit (TLAP) – A permit issued by the TCEQ for surface or subsurface disposal of treated wastewater effluent.

• Texas Pollutant Discharge Elimination System (TPDES) Permit – A permit issued by the TCEQ for disposal of treated wastewater effluent into waters of the state.

• Wastewater Collection System – The pipe system for collecting and carrying water and water-carried wastes from domestic and industrial sources to a wastewater treatment plant.

• Wastewater Facilities – The pipes, conduits, structures, equipment and processes required to collect, convey, treat domestic and industrial wastes, and dispose of or reuse the treated effluent.

• Wastewater Treatment Plant – An arrangement of pipes, equipment, devices, tanks and structures for treating wastewater and industrial wastewaters.