To: Members of the Castle Rock Water Commission
From: Mark Marlowe, P.E., Director of Castle Rock Water
Shawn Griffith, Assistant Director of Operations
John Chrestensen, Operations Manager
Title
Discussion/Direction: Request for Two Raw Water System Operator Staff with Excavator and Truck Purchase for Raw Water Operations Team and first Quarter Budget Amendment
Town Council Agenda Date: February 18, 2025
Body
________________________________________________________________________________
Executive Summary
The purpose of this request is to add two Full Time Equivalent (FTE) Raw Water System Operator I-IV positions, reporting to the Field Services Water Distribution team, a new ¾ ton work truck with a utility bed, and a new Cat 308 mini excavator. To fund these new employees and equipment, we will be utilizing a first-quarter budget amendment, in 2025 for a total amount of $517,594, (See Attachments A, B, and C).
The goal of Castle Rock Water (CRW) is to consistently increase the use of renewable water for treatment and distribution. CRW is moving away from non-renewable groundwater sources, found primarily in the Dawson, Denver, and Arapahoe aquafers. CRW’s ultimate goal is to be able to provide 75% renewable water for distribution by 2050. In pursuit of this goal, CRW has been making significant investments in acquiring rights for renewable water sources and building needed infrastructure to convey, store, and treat renewable water.
Currently, CRW receives renewable water from multiple sources, including:
• 14 alluvial wells along East Plum Creek
• Two surface water diversions on Plum Creek. These two diversions are the Plum Creek Diversion (PCD) and CR-1 Diversion (CR-1)
• Purchasing imported water from the South Metro Water Supply Authority through the Water Infrastructure and Supply Efficiency Project (WISE)
These sources are essential to ensure that CRW has the available water to meet and exceed the demands of its service areas, now and in perpetuity. While these sources are a vital part of our plan to ensure long-term water, the infrastructure associated with them requires a significant amount of maintenance and operator involvement for consistent and efficient operation, when compared to deep groundwater wells. Although they require more maintenance, the majority of this maintenance can be performed by in-house staff, reducing the need and cost of scheduling specialized maintenance contractors and equipment.
Alluvial wells and diversions also provide a significant cost benefit in terms of electrical use. The water from our renewable sources is either at surface elevation or in the shallow (<100’ deep) stream alluvium, whereas groundwater sources range from 600’- 2,500’ below surface elevation. Pumping water from these depths requires large amounts of electricity to run high-horsepower pump motors. The use of these sources also reduces the environmental impacts caused by the depletion of underground aquifers.
The most impactful staff deficiency that these raw water sources have created is the operation and maintenance of the two surface water diversions. Diversion maintenance is labor-intensive requiring multiple hours of maintenance per day to be at peak efficiency. Additionally, the reactive maintenance and repairs associated with the pumping infrastructure need to be considered.
Required daily diversion maintenance is the result of two contributing factors:
• The first is organic material in the stream, which adheres to the screen filters. This material consists of tree leaves, algae, and other vegetation that float in the stream and get stuck to the screens as water passes through them. The buildup of this material significantly reduces the amount of water that can flow through the screen. When this happens, an operator must go to the site and manually clean the screens to restore flow.
o This activity is typically needed 1 to 3 times per day and takes 30 minutes to 2 hours for 1 to 2 operators depending upon stream flows and traffic. Labor ranges from 11 to 84 hours per week.
• The second and most impactful factor is the transference of sediment in Plum Creek. Plum Creek has a significant amount of erosion causing sand loading that constantly migrates along the bed of the stream. This sand builds up in front of the diversions and eventually moves into the structures, impeding water flows, and causing damage to the pumping and treatment plant equipment. Scheduled and reactive manual sand removal and mitigation is the only option available to remove the sand build-up and reduce equipment damage. Although both diversions have the same issue, differences in the design and the location of each diversion require significantly different processes and equipment to complete maintenance.
There are many variables involved with diversion raw water capture, but it has been proven that regular proactive maintenance increases raw water production. For example, the average daily production in gallons per day (GPD) at CR-1, over the past three years, is shown in the chart below:
• 2022: 571,324 GPD
• 2023: 611,863 GPD
• 2024: 1,058,490 GPD
The dramatic increase in 2024 can be attributed to the regularly scheduled maintenance program that was implemented in 2024. It is anticipated that a scheduled maintenance program implemented by dedicated raw water staff at PCD will have similar results.
CR-1 Diversion
Located on East Plum Creek in Castle Rock just south of the Plum Creek Water Purification Facility (PCWPF). This diversion consists of a screened section of an exposed 24” pipe that runs perpendicular to the stream flow. The screen filter is located in the center of the creek. This diversion operates by allowing surface water to infiltrate the pipe and fill a wet well, where it is then pumped directly to the raw water blending tank at PCWPF. The rated capacity of CR-1 is 5.6 cubic feet per second (CFS), or 3.6 million gallons per day (MGD). In April of 2022, the diversion captured a record amount of 2.7MGD.
The most effective way to manage the sand loading at this site is to utilize a large high-volume vacuum truck (Vac Truck) to clean the deposited sand out of the wet well. This work is scheduled twice per week during periods of high stream flows (every Monday and Thursday) and once per week (every Wednesday) during periods of low stream flows.
• Currently, vac truck work is typically performed by members of the Field Services Collection system operation team, removing the team from the primary duties of operating and maintaining the Wastewater Collection system.
• Labor: Depending on the amount of sand that has accumulated in the vault, 2 operators, trained and licensed to operate a vac truck, 2 hours per visit to complete. Labor ranges from 4 to 24 hours per week.
PCD Diversion
Located on Plum Creek in Sedalia, just downstream from the confluence of East and West Plum Creeks, roughly five miles downstream of Plum Creek Water Reclamation Authority’s Wastewater Treatment Facility outfall. This diversion sits at the edge of the stream running parallel to the stream flow. It operates by blocking the stream flows with a weir wall and the use of slide gates to create a pool of water that then flows over and through the screens. The rated capacity of PCD is 40 CFS or 25.8 MGD. The water then flows through an underground structure that fills the wet well of the Plum Creek Diversion Pump Station (PCDPS), where it is pumped to Castle Rock Reservoir 1 (CRR1) and the soon-to-be-completed Castle Rock Reservoir 2 (CRR2) for storage. The stored water in CRR1/CRR2 is then pumped to PCWPF through the PCD Pump Station and to the Ravenna Golf Course through the Ravenna Pump Station.
The sand loading issue at the Sedalia site is significantly more impactful and requires more frequent intervention to keep it from interrupting diversion operations and causing damage to the pump station, piping, and pumps. Five main forms of routine sand removal and mitigation operations are needed to keep this diversion and pump station operating consistently:
• Setting and maintaining large sandbags (Super Sacks) in the stream channel
o A large excavator with at least two operators is required to set the sacks. Adjustment of the Super Sacks is critical due to frequent stream flow changes. Relocating the Super Sacks based on the stream flows creates the proper scour depression in front of the intake structure and increases the amount of water that can flow into the structure. Stream erosion and flood events necessitate continuous Super Sack maintenance for efficient diversion operations.
o Labor: 2 operators, 4 to 6 hours to complete, and is needed 1 to 2 times per month, depending upon stream flows and storm events.
• Scouring sand that builds up in front of the intake structure
o Operators must go to the site two or three times per day to operate the slide gates, which allow built-up sand in front of the diversion structure to scour downstream.
o This operation is typically completed by members of the Treatment Services team, removing staff from the primary duties of operating the treatment plants and maintaining water and water quality in the distribution system.
o Labor: typically takes 1 operator, 1 hour on-site, and 1 hour of travel time. Labor ranges from 28 to 42 hours per week.
• Removing accumulated sand from inside of the intake structure
o A mini excavator and a dump truck are used to scoop the sand out and truck it to a stockpile location. Removing the sand from the intake structure requires a skilled operator to carefully dig inside the concrete structure and place the sand in a dump truck.
o This operation requires the use of equipment close to the fragile and expensive stainless-steel screens; only expert-level heavy equipment operators can perform this task. As such, it is completed by senior members of the Field Services team, removing staff from the primary duties of operating and maintaining the Stormwater, Water Distribution, and Wastewater Collection systems.
o Labor: 2 operators 3 to 5 hours to complete and are needed 1 to 2 times per week. Labor ranges from 6 to 30 labor hours per week.
• Removing accumulated sand from the downstream side of the diversion
o A large excavator is used to enter the stream and dig out sand from behind the diversion. The sand is then stockpiled on the stream bank where it is later loaded into dump trucks and trucked to a stockpile location.
o This operation requires the use of large heavy equipment close to the diversion structure and in the stream flow, only expert-level heavy equipment operators can perform this task. As such, it is completed by senior members of the Field Services team, removing staff from primary duties of operating and maintaining the Stormwater, Water Distribution, and Wastewater Collection systems.
o Labor: 3 operators 6 to 12 hours to complete and are needed once a week to once every other week. Labor ranges from 9 to 36 hours per week to complete.
• Removing accumulated sand from the sand vault, 42’’ pipe, and wet well at PCDPS
o Over time smaller suspended particles of sand, pass through the filter screens in the diversion. Sediment deposits build up inside the sand vault, the 42’’ diameter pipe, and the wet well of the pump station.
o As sand accumulates and travels through the system it causes a loss of production as well as significant damage to the pumps. Recently, this issue caused a catastrophic failure of one of the small-duty pumps inside the pump station, in the middle of the summer demand season. This damage required the pump to be taken out of service and sent in for repairs. The overall cost for the pump repair and the crane service to remove and reinstall the pump was $26,122. The repair took four months to complete.
o Due to the long lead time involved in getting these pumps repaired and the loss of pumping capacity when they are out of service, CRW purchased a spare pump, stored at the pump station, to reduce the downtime during pump repairs. The cost of the spare pump was $67,232.
o This work is a three-step process:
§ A vac truck is used to suck out the deposited sand from the sand vault.
§ Operators enter the 42’’ pipe with fire hoses to blast the sand from the pipe into the sand vault and wet well.
§ Operators enter the wet well and utilize shovels and fire hoses to liquefy and move the sand to the sand pump, pumping it out of the wet well.
o Labor: This complex maintenance operation requires 12 operators 10 to 15 hours to complete and was required 3 times in 2024. The total labor hours for this task range from 360 - 540 annually or roughly 7 to 10 labor hours weekly to complete.
CRR1 and CRR2 Raw Water Reservoirs
o CRR1 and CRR2 are raw water reservoirs that store creek water pumped from the PCD.
o The water stored in these two reservoirs is then pumped through the PCDPS to PCWPF.
o This water in the reservoirs is used for potable drinking water, close water quality monitoring is required.
o The required frequency of water quality monitoring changes seasonally and typically increases during late spring through the summer demand season.
§ Samples are typically taken twice in May and then weekly from June - October. Operators must launch a boat to pull water samples from specific locations and water depths from the reservoir.
§ Labor: 2 operators 3 hours to complete, 22 times per year. The total labor hours for this task are 2.5 hours per week, 132 hours annually.
Alluvial Well Maintenance
o There are 14 wells in the shallow stream alluvium under East Plum Creek, classified as Ground Water Under the Direct Influence of Surface Water (GWUDI) wells. Because of this, the raw water from these wells has higher concentrations of Iron, Manganese, and organic material, than deep groundwater wells. As a result, these wells become fouled quickly as material builds up on the well equipment and piping, increasing maintenance needs.
o To keep up with this maintenance and ensure consistent flows, CRW plans to conduct rehabilitation (rehab) work each year.
o This rehab work consists of hiring a specialized well contractor to pull and clean the well equipment, bail accumulated sediment from the well casing, and wash the well screen to remove iron deposits and other materials that may clog the screen.
o Once the equipment has been pulled by the well contractor, CRW staff will complete an ice-pigging operation, to clean the piping from the wellhead to the metering vault.
o Labor: requires the use of a vac truck as well as several other specialized pieces of equipment, requiring 5 operators roughly 10 hours to complete. Total labor hours for this task are 4 hours per week, with approximately 200 labor hours annually.
Meadow Ditch Water Rights Infrastructure
o CRW recently acquired Meadow Ditch water rights and infrastructure.
o Maintenance activities include those at Meadows Ditch (Indian Creek), Deer Creek (upstream of Chatfield Reservoir), Cook Creek (tributary to East Plum Creek), and the Highline Ditch water rights (along East Plum Creek), among others.
o Maintenance activities include vegetation and debris removal, streambed maintenance, flow measuring devices maintenance, and creating field reports for the supervisors.
o As these resources are new to CRW, we do not have a full understanding of the amount of or frequency of maintenance activities that will be required. However, operating and maintaining this infrastructure will increase the total labor hours associated with renewable water resources.
When the total labor hours are added up for the routine maintenance requirements at both diversions, the raw water reservoirs, and the alluvial wells, the CRW Operations team dedicates between 74 to 239 labor and equipment hours each week, or 3,817 to 12,397 annually to ensure consistent renewable water operations. These labor hours do not include the hours that will be needed to maintain the Meadow Ditch Water Rights infrastructure and will be higher than this in 2025.
The teams primarily impacted by this additional maintenance are:
• Water Treatment Operations
• Field Services Stormwater Maintenance Operations
• Field Services Wastewater Collections Operations
• Field Services Distribution Operations
• Plant Maintenance
• Water Quality
Performing these maintenance duties removes staff from the primary duty of treating water and repairing and maintaining Town infrastructure. The additional raw water maintenance work causes Operation team problems, such as:
• Extended assigned project completion timelines
• Difficulty reaching annual maintenance goals
• Sudden storm-related re-prioritization of tasks
• Planned project backlogs
• Increases in required staff overtime
All of these issues may contribute to a lack of employee job satisfaction, stress, and burnout.
Discussion
CRW currently has two large Capital Improvement Projects (CIP) underway that will be completed within the next three years. These projects are:
• The construction of Castle Rock Reservoir 2 (CRR2) and expansion of Castle Rock Reservoir 1 (CRR1), with project cost for Design and Construction at $30 million.
• The expansion of PCWPF from 6 million gallons per day (MGD) to 12 MGD, with project cost for design and construction at $74 million.
These projects will increase CRW’s ability to store and treat renewable water and will rely on the two surface water diversions operating at the full rated capacity of 29.4 MGD combined while ensuring that the alluvial wells operate at maximum efficiency. In 2024, the average combined production of the diversions was 1.44 MGD with the highest single-day production of 7.96 MGD. Fully operational and reliable diversions, particularly during times of Free River, will allow the maximization of water rights, and increase the volume of stored water in CRR1 and CRR2 for treatment at PCWPF.
The addition of two Raw Water System Operator IV positions as well as the purchase of a utility truck and a dedicated diversion maintenance mini excavator will benefit CRW and the Town by providing the staffing levels required for:
• Consistently operating the surface water diversions in a safe, efficient, and cost-effective manner.
• Consistent focus on the repair, maintenance, and production goals in all operational systems.
• Maximizing available renewable water for treatment.
• Increasing in-house staff competency.
• Creating standard operating procedures for diversion maintenance.
• Moving from reactive maintenance to routine and predictive maintenance cycles at the diversions.
• Operating the raw water storage reservoirs at full potential (CRR1/CRR2).
• Creating the framework needed to meet CRW’s goal of providing 75% renewable water by 2050.
• Increasing available water at PCWPF, up to 12 million gallons per day, once the plant expansion is complete in 2028.
Adequate staffing is a requirement for safety, maintaining current levels of service, having the available water resources for treatment needs, and the efficient, cost-effective production of high-quality water, which is a valuable benefit for CRW Customers.
This request takes into account the following tactics or initiatives from the CRW Strategic Plan:
• Strategic Goal Tactic 1-2-2: “Complete the construction of CRR2 and the expansion of CRR1.” With the additional volume of surface water storage that will be available shortly, maximizing the ability to divert surface water at PCD is imperative to meet our goal of 75% renewable water use by 2050.
• Strategic Goal Tactic 1-2-8: “Optimize the amount of water stored in all reservoirs each year.” With the addition of two Raw Water System operators, dedicated staff will be available to operate the PCD and CR-1 Diversions and help keep renewable water flowing to the reservoirs and to PCWPF for treatment.
• Strategic Goal Tactic 1-2-18 and 19: “Upgrade PCD to maximize its operational ability relative to the current permitted capacity.” The new staff will become experts in the operation of diversions, obtaining a clearer understanding of needed upgrades essential for operational optimization.
• Strategic Goal Tactic 5-3-26: “Refine reservoir monitoring procedures to help anticipate toxic algal blooms.” With this addition, CRW will have staff members at the reservoir site nearly every day, available to inspect, test, and monitor reservoir water quality frequently, responding quickly to issues.
Next Best Alternative(s): Is there an alternative that would meet or partially meet the requested objective? Are there any consequences?
One option is to continue to operate these diversions by utilizing the members of the various teams in Operations fitting these tasks into their schedules, as needed. However, this will continue to cause deficiencies in the individual work groups by adding additional workload. Also, diversion operation may not be optimized, which will impact diversion production capabilities, limiting the availability of renewable water.
Another alternative that would partially meet the objective would be to utilize a contractor to perform the sand removal and dredging operations at the diversions. This option would reduce the staff and equipment time needed to perform these tasks but would require a staff member to be onsite to coordinate, oversee the work, and operate infrastructure. While this option would alleviate some of the staffing and equipment needs, the rates for the contractor will likely exceed the annual cost of having dedicated FTEs. Also, this option has been utilized in the past with limited success, due to the availability of the contractors.
Budget Impact
Funds for this request will need to be added to the Water Resources accounts, as shown in the charts below:
For Staff Salaries & Wages:
|
Fund Name |
Account Number |
Spilt |
|
Field Services |
211-4345-443.10-10 |
50% |
|
Treatment Services |
211-4360-443.10-10 |
50% |
For Equipment and Vehicle:
|
Fund Name |
Account Number |
Spilt |
|
Field Services |
211-4345-443.70-30 |
100% |
Staff Recommendation
Staff recommends an amendment to the 2025 budget to add two additional FTEs, a new work truck, and a new Mini Excavator.
Attachments
Attachment A: Raw Water System Operator BCR Form
Attachment B: Asset Addition Estimate Template - Ford F250
Attachment C: Asset Addition Estimate Template - Cat 308