Chatfield Watershed Authority 2019 Annual Report We Protect the Water You Enjoy
The Chatfield Watershed Authority promotes protection of water quality in the Chatfield Watershed for drinking water supplies, recreation, fisheries, and other beneficial uses.
2019 Annual Report Page | 1
The 2019 Annual Report is the annual water quality summary and status report presented by the Chatfield Watershed Authority to communicate the water quality of Chatfield Reservoir and its watershed, highlighting information required by the Colorado Water Quality Control Commission in Control Regulation #73.
Table of Contents Chatfield Watershed Authority ...... 1 Reservoir regulatory compliance ...... 4 Chatfield reservoir tmal ...... 7 Watershed and Reservoir monitoring program ...... 10 Chatfield storage reallocation project ...... 15 Wastewater treatment plants ...... 17 Site location applications ...... 19 Regulated stormwater sources ...... 21 Education and outreach ...... 23 Progress to promote water quality protection ...... 26 Chatfield Watershed Authority Members ...... 27
Chatfield Watershed Authority
The Chatfield Watershed Authority (the Authority) was established in 1984 when the Governor of Colorado designated the Authority as the 208 Management Agency, in accordance with the Federal Clean Water Act. The Authority’s mission is to promote protection of water quality in the Chatfield Watershed for recreation, fisheries, drinking water supplies, and other beneficial uses. The Authority preserves these beneficial uses in Chatfield Reservoir and the Watershed through promotion of point source, nonpoint source and stormwater controls.
The Authority continues to implement Colorado Water Quality Control Commission Chatfield Reservoir Control Regulation, 5 CCR 1002-73 (Control Regulation No. 73); and coordinating with state and federal agencies regarding water quality control measures.
The Authority is comprised of stakeholders within the 400 square mile watershed and is comprised of the Plum Creek basin and portions of the South Platte River basin (from the outfall of Strontia Springs Reservoir to Chatfield Reservoir, including the Massey Draw and Deer Creek sub-basins). The members develop and implement projects to protect the watershed, reservoir health and water quality. Opportunities exist within the watershed to address the chemical, physical and biological constituents (pollutants) that impact the watershed and reservoir. Some examples of this include phosphorus removal in wastewater treatment, stabilizing degraded streambanks, mitigating runoff from agricultural lands, minimizing leachate from septic systems, controlling runoff from wildfire burn areas, and providing public education for reducing contamination from the actions of people.
The Authority member’s jurisdiction and service are boundaries as well as the Chatfield watershed boundary are shown on Figure 1. The 5-member Board of Directors (Board) is comprised of three elected officials representing Douglas County, Jefferson County, and the Town of Castle Rock; one wastewater district representative; and one representative for other members. The Board continues to implement Control Regulation No. 73. The Board meets regularly to address policy and fiscal issues.
2019 Board Members Board Chair: Director George Teal, Town of Castle Rock Councilman Board Vice-Chair: Director Lesley Dahlkemper, Jefferson County Commissioner Board Director: Lora L. Thomas, Douglas County Commissioner Board Director of Water and Sanitation Members: Barbara Biggs, Roxborough Water & Sanitation District Manager Board Director of Other Members: Alison Witheridge, Denver Water
2019 Annual Report Page | 1 The Technical Advisory Committee (TAC) is a standing committee that meets monthly to address technical and scientific matters, serving at the pleasure of the Board. Other standing committees are formed, as necessary, to address specific issues at the Board’s request.
2019 Technical Advisory Committee Representatives Jefferson County: Chair, Patrick O’Connell Dominion Water & Sanitation District: Vice-Chair, Mary Kay Provaznik Castle Pines Metropolitan District: Jeff Coufal Centennial Water & Sanitation District: Julie Tinetti City of Littleton: Carolyn Roan Denver Water: Craig Lamacraft Douglas County: Jim Dederick Louviers Water & Sanitation District: Ron Beane Roxborough Water & Sanitation District: Ronda Sandquist Plum Creek Water Reclamation Authority: Weston Martin Perry Park Water & Sanitation District: Diana Miller Town of Castle Rock: David Van Dellen Town of Larkspur: Paul Grant
2019 Annual Report Page | 2 Figure 1. Chatfield Watershed Authority Watershed Boundary and Member Entities.
2019 Annual Report Page | 3 Reservoir regulatory compliance In 2019, Chatfield Reservoir was in compliance with Regulation 38 chlorophyll-a (chl-a) and phosphorus standards (Regulation 38, Water Quality Control Commission 5 CCR 1002-38). CHLOROPHYLL-α The chlorophyll-α (chl-α) standard in the reservoir is 10 µg/L, with an allowable exceedance frequency of one time in five years. The Colorado Water Quality Control Commission (WQCC) adopted an assessment threshold of 11.2 µg/L to be used to determine compliance with the standard. The chl-α standard is the growing season (July through September) average. In 2019, the chl-α average was 10.7 µg/L, slightly above the standard, but below the assessment threshold. Pursuant to the assessment protocols because there has only been one exceedance of the assessment threshold in the last five years (2016); the reservoir remains in compliance with the standard (Figure 2).
Observed 2019 chl-α concentrations in Chatfield Reservoir are depicted in Figure 3. Chl-α levels were met for the growing season (July through September).
Figure 2. Growing Season Average Chlorophyll α Concentrations, Chatfield Reservoir, 1983-2018. Historic Chlorophyll α Growing Season Average Concentrations (1983-2019) 30 Historical Chl α Goal (17 µg/L) Chl α Assessment Threshold (11.2 µg/L) Chl α Standard (10 µg/L)
25
20
(µg/L) α 15
10 Chlorophyll Chlorophyll
5
0
Figure 3. Observed 2019 Chlorophyll α Concentrations, Chatfield Reservoir, 2019.
The July-September 2019 Chatfield Reservoir Centroid Chlorophyll α 35 growing season average in 2019 was 10.7 µg/L, below 30 2019 Growing Season the assessment threshold 25 of 11.2 µg/L (see Figure 3).
(μg/L) 20 α
In 2019, Chatfield Chl 15 Reservoir continued to be 10 in compliance with the chlorophyll-α water quality 5
standard. 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2019 Annual Report Page | 4 The chl-α concentrations observed result from background, point source and nonpoint sources of nutrients and internal loading. In 2019, Cyanophyta concentrations ranged from 1,079 to 43,086 algal cells/mL, which are significantly lower than the Cyanophyta levels in 2018 which ranged from 857 to 281,256 algal cells/mL. The highest concentrations occurred in August (Figure 4).
Algae (genera Anabaena, Ankistrodesmus and Aphanocapsa) typically correspond with elevated chl-α measurements. Some species of cyanobacteria can convert nitrogen gas to biologically available forms of nitrogen, serving as an additional source of nitrogen to the reservoir system. Cyanophyta were the predominant algae observed in the majority of the April - October sampling events, with the exception of Bacilliariophyta, which were higher than the Cyanophyta in May (Figure 5).
Figure 4. 2019 Phytoplankton Monthly Summary - Phytoplankton samples taken in the reservoir during 10 sampling events from April through October 2019. Cyanophyta, also sometimes called blue-green algae, are shown to peak in August at 43,086 algal cells/mL
2019 Phytoplankton Concentration: Reservoir Centroid
1,000,000
100,000
10,000
1,000 Agla Agla cells/mL 100
10
1 Apr May June July Aug Sept Oct
Cyanophyta Chlorophyta Bacillariophyta Chrysophyta Cryptophyta Haptophyta Pyrrhophyta
Figure 5. 2019 Phytoplankton Speciation Variability – Cyanophyta (cyanobacteria) were a predominant algae observed in May through October, whereas Bacillariophyta predominated in May. 2019 Phytoplankton Speication by Percentage: Reservoir Centroid 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
4/24/2019 5/13/2019 6/10/2019 7/8/2019 7/22/2019 8/5/2019 8/19/2019 9/3/2019 9/23/2019 10/14/2019
Cyanophyta Chlorophyta Bacillariophyta Chrysophyta Cryptophyta Haptophyta Pyrrhophyta
2019 Annual Report Page | 5 TOTAL PHOSPHORUS
The total phosphorus (TP) July through September growing season average was 26.7 µg/L, which is below the standard of 30 µg/L and also below the assessment threshold of 35 µg/L. Chatfield Reservoir does not exceed the one in five-year assessment allowance. A review of TP compliance with the water quality standard from 1983 to 2019 is illustrated in Figure 6. The TP growing season average has remained below the water quality assessment threshold of 35 μg/L since the standard changed in 2009. The monthly TP concentrations observed in 2019 in Chatfield Reservoir are shown in Figure 7.
Figure 6. Growing Season Average Total Phosphorus Concentrations, Chatfield Reservoir, 1983-2018.
Historic Total Phosphorus Growing Season Average Concentrations (1983-2019) 50 Historical TP Standard (27 µg/L) TP Assessment Threshold (35 µg/L) TP Standard (30 µg/L) 45 40
35 g/L) µ 30 25 20 15
Total Phosphorus ( Phosphorus Total 10 5 0
Figure 7. Monthly Total Phosphorus Concentrations, Chatfield Reservoir, 2019.
The July-September 2019 Chatfield Reservoir Centroid Total Phosphorus 65 growing season average in 60
2019 was 26.7 µg/L, below 55 2019 Growing Season the assessment threshold 50 45 of 35 µg/L (see Figure 6). In 40
2019, Chatfield Reservoir 35
continued to be in (μg/L) TP 30 25 compliance with the total 20
phosphorus water quality 15
standard. 10 5
0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2019 Annual Report Page | 6 Chatfield reservoir tmal The phosphorus Total Maximum Annual Load (TMAL) of 19,600 pounds/year at a median flow of 100,860 acre- feet/year was revised by the WQCC in 2009, based on statewide reservoir data and a probabilistic model describing the linkage between watershed TP loads and in-lake TP concentrations.
The Authority completed the development and calibration of an initial watershed model in 2016. In 2019, plans were developed for additional model improvements in 2020 to allow for modeling of the effects of possible watershed improvements. The initial model improvements were started in late 2019 with continued development of the watershed model planned for 2020.
The Authority continues to collect water quality data (over 20 years of monitoring) and since 2016 has collaborated with the Chatfield Reallocation Mitigation Company (CRMC) on data collection efforts pursuant to the Memorandum of Understanding between the two agencies.
For Chatfield Reservoirthe Authority continues to coordinate with the CRMC regarding data collection and calibration of the reservoir model (required as part of the water quality adaptive management program). The Authority currently serves on the Chatfield Reservoir Model Coordination Committee (RMCC), which was tasked with overseeing the development of a two-dimensional, hydrodynamic water quality model for the reservoir. Development of a model was funded by the CRMC as part of the Chatfield Storage Reallocation Project (CSRP). The independently peer- reviewed model has been calibrated for the period of 2013 through 2016. Sensitivity analysis runs were completed in 2018. The Chatfield Reservoir Water- Quality Model Documentation Report was completed by Hydros in December 2018. Future tasks will include ongoing annual model updates (with more recent data) and predictive runs to support the Chatfield Reallocation project management. After storage begins in 2020, potential impacts from the Chatfield Reallocation Project, if any, will be evaluated on a yearly basis. 2019 TP CONCENTRATIONS – INSTREAM AND RESERVOIR Average monthly TP concentrations for 2019 at the Chatfield Reservoir Centroid, Chatfield Reservoir Outflow, Plum Creek Inflow, and South Platte Inflow are depicted in Figure 8. Refer to Figure 12 for these sampling locations. Plum Creek TP concentrations were highest for all months of the year in comparison to South Platte Inflows. Calculated TP load The calculated annual TP load is the sum of the average monthly loads. The 2019 annual TP load to the reservoir totaled 9,105 pounds at an inflow of 115,047 acre-feet. This is compared to the TMAL of 19,600 pounds at an inflow of 100,860 acre-feet. Figure 9 shows the calculated annual TP loads to Chatfield Reservoir from 1986 to 2019. Figure 10 shows the Chatfield Reservoir calculated annual inflows from 1986 to 2019. A comparison of the 2019 inflows and TP load contributions is presented in Figure 11.
The relative TP loading from sources is typical compared to historic TP inputs. This year, TP loading from Plum Creek was 3,532 pounds, or 39% of total input, compared to 4,944 pounds from the South Platte River, or 54% of total input. Direct precipitation on Chatfield Reservoir, alluvial inflows, and other direct flow sources contributed approximately 629 pounds, or 7% of total input.
2019 Annual Report Page | 7
Figure 8. 2019 Average Monthly Total Phosphorus Concentrations in Chatfield Watershed and Chatfield Reservoir.
2019 Total Phosphorus Average Monthly Concentration Reservoir Centroid South Platte Inflow Plum Creek Inflow Reservoir Outflow 180
160
140
120
100
80
60
40 Total Phosphorus (µg/L) Phosphorus Total 20
0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Figure 9. Calculated Total Phosphorus Load to Chatfield Reservoir (1986 – 2019).
Chatfield Reservoir: Calculated Annual TP Load (1986 - 2019) 70,000
60,000
) 50,000 lb/yr 40,000
30,000
20,000 Total Phosphorus( Total
10,000
0
2019 Annual Report Page | 8 Figure 10. Chatfield Reservoir Calculated Annual Inflow (1986 – 2019).
Chatfield Reservoir: Calculated Annual Inflow (1986 - 2019) 450,000
400,000
350,000
300,000
250,000
200,000
150,000
100,000 Chatfield Inflow Inflow (AF/yr) Chatfield
50,000
0
Figure 11. 2019 Chatfield Reservoir Inflows and Total Phosphorus Loads.
2019 Chatfiled Reservoir Inflows and Total Phosphorus Loads Inflow (115,047 AF Total) TP Load (9,105 lbs Total)
100 90 97,625 AF 80 70 60 4,944 lb TP 50 3,532 lb TP 40 30
Percent Contribution,Percent % 20 12,975 AF 556 lb TP 10 1,763 AF 2,684 AF 73 lb TP 0 South Platte River Plum Creek Direct Precipitation Alluvial Inflow
2019 Annual Report Page | 9 Watershed and Reservoir monitoring program Since 1984, the Authority and its members have monitored water quality in the reservoir and upstream in the watershed and has undertaken measures to protect water quality in the Watershed through voluntary funding contributions and grants. The Authority, in coordination with its membership agencies, implements point source, nonpoint source and stormwater controls pursuant to the Chatfield Reservoir Control Regulation #73 (5 CCR 1002-73) to protect water quality and beneficial uses of the Reservoir. CHATFIELD RESERVOIR The Authority collects water quality data to determine reservoir chlorophyll levels, temperature, dissolved oxygen concentration, phosphorous concentrations, nitrogen concentrations and inflow quantities. The members develop and implement nonpoint source and stormwater projects which benefit the watershed and reservoir. The Chatfield Watershed Plan identified opportunities within the watershed to address the chemical, physical and biological constituents (pollutants) that impact the watershed. Some examples include phosphorus reductions from stabilizing degraded streambanks, mitigating runoff from agricultural lands, minimizing leachate from septic systems, controlling runoff from wildfire burn areas, and providing public education for reducing contamination from the actions of people.
The monitoring program characterizes water quality and determines regulatory compliance in the reservoir. Surface water samples are collected in the following locations:
South Platte Inflow
Plum Creek Inflow
South Platte Arm (in Chatfield Reservoir)
Plum Creek Arm (in Chatfield Reservoir)
Reservoir Centroid (Chatfield Reservoir)
Reservoir Outfall
The constituents are monitored monthly when ice has melted off the reservoir. During the growing season (July through September), reservoir sampling is conducted twice per month. To better understand reservoir dynamics, the Authority collects water column measurements, including the epilimnion and hypolimnion layers, at various depth intervals. All water quality data are available on the Authority’s website: www.chatfieldwatershedauthority.org
2019 Annual Report Page | 10 Figure 12. 2019 Chatfield Watershed Authority Sampling Locations and Constituents.
2019 Annual Report Page | 11 Plum creek watershed monitoring system In the Plum Creek basin, watershed monitoring continued in 2019 through voluntary sampling efforts by the Plum Creek Water Reclamation Authority (PCWRA); monitoring locations are shown in Figure 12. The objective of the Plum Creek monitoring program is to better characterize water quality in Plum Creek and identify potential nonpoint source pollutant sources, a variety of which have already been identified in the watershed, including:
Stormwater runoff from historic urbanized and rural areas
Leachate from unmaintained septic systems, agricultural activities, including runoff from overgrazed agricultural lands
Runoff from wildfire burn areas
Runoff from impervious areas
Erosion from degraded streambanks (Chatfield Watershed Plan, May 2015)
Further data collection is needed, contingent on available resources, to identify and quantify phosphorus sources in the Plum Creek basin. The 2019 Plum Creek water quality observations included the following:
Stream bank Erosion. Historically, there was significant streambank erosion on Plum Creek. This eroding area contributed significant sediment, and likely TP. As part of the mitigation for the CRMC reallocation project, stabilization of a portion of Plum Creek in the State Park has been completed. Additional stabilization on Plum Creek will continue to be evaluated by watershed stakeholders
E.coli. Although variability is evident at all monitoring sites, the central tendency (geometric mean) of observed E. coli remains below the water quality standard of 126 organisms/100 mL (Figure 13). In 2015, the Authority commenced a molecular source tracking monitoring program to help understand potential sources of E. coli. Sources identified in East Plum Creek, West Plum Creek, and at the inlet to the Reservoir included human, horses, cattle, beaver and general Bacteriodetes.
Figure 13. E. coli in Plum Creek Drainage Area, 2019 2019 Plum Creek Drainage Area - E. coli Maximum Geometric Mean 10,000
1,000
100
E. coli (MPN/100mL) E. coli 10
1
2019 Annual Report Page | 12 Total phosphorus. TP concentration generally increases from upstream to downstream for both East Plum Creek and Plum Creek (Figure 14). Average Total Phosphorus in West Plum Creek decreased between Perry Park and the confluence with East Plum Creek. Total Phosphorus concentrations have historically been observed to be relatively high at East Plum Creek above the confluence with Plum Creek (Site EPC-11.1), compared to other sites in Plum Creek watershed. In 2019 the average TP at this site was 193 μg/L, compared to the 2018 average of 185.0 ug/L and the 2017 average of 245.0 μg/L.
Figure 14. Total Phosphorus in Plum Creek Drainage Area, 2019
2019 Plum Creek Drainage Area - Total Phosphorus Average Maximum Minimum 300
250
200
150
100 Total Phosphorus,(ug/L) Total 50
0
Considerable monitoring has been performed in the Plum Creek watershed. This effort provides the ability to evaluate conditions on both a temporal and spatial scale.
Chatfield Watershed Plan 2015
2019 Annual Report Page | 13 Total suspended solids. The average TSS concentration is an indicator of sediment and high precipitation events. The highest average TSS concentration observed in 2019 was at Site EPC-11.1 (East Plum Creek above the confluence with Plum Creek) at 64.7 mg/L. This was also the highest average TSS site in 2018 (73.6mg/L) and 2017 (201.4 mg/L) (Figure 16).
The average TSS at site EPC-33.6 (East Plum Creek Upstream of Larkspur) was 7.9 mg/L in 2019 compared to 4.7 mg/L in 2018 and 1.4 mg/L in 2017. All of the other sites decreased in average TSS concentrations in 2019 compared to 2018, potentially indicating less erosion and sediment loading to Plum Creek for 2019.
Figure 15. Total Suspended Solids in Plum Creek Drainage Area, 2019 2019 Plum Creek Drainage Area - Total Suspended Solids Average Maximum Minimum 100
90
80
70
60
50
40
30
20
Total SuspendedSolids,(mg/L) Total 10
0
Total Phosphorus vs. Total Suspended Solids. The relationship between TP and TSS is complex. The highest TSS and TP data collected in the watershed generally occurred during the spring runoff months during high flow, (April-June). Additionally, TP and TSS typically had an increasing trend through the watershed. 2019 showed some slight decreases (TSS) below the confluence of East and West Plum Creek. The TP vs TSS relationship, along with identification of potential nonpoint sources of TP, will be further evaluated as monitoring in Plum Creek basin continues.
2019 Annual Report Page | 14 Chatfield storage reallocation project Overall construction of the Chatfield Storage Reallocation Project (CSRP) commenced in late 2017. The Chatfield Reservoir Mitigation Company (CRMC) worked closely with its contractors to complete their portions of the CSRP, with the goal to have all improvements completed and approved by U.S. Army Corps of Engineers (USACE) before spring of 2020. CRMC has also utilized construction oversight services from each of the main design consultants (Muller, HDR, and CH2M) to ensure that construction meets specifications.
In November 2017, CRMC entered into a contract with Concrete Express, Inc. (CEI) to construct the Plum Creek Environmental Mitigation Project. CEI was tasked with constructing a new stream system, complete with the installation of a new main channel and secondary channels, plus several riffle-drop structures, guide banks and sloughs. A significant revegetation effort is associated with the project, which involved the installation of over 54,000 native potted plants, shrubs, and trees. CEI completed construction of the Plum Creek Environmental Mitigation Project Downstream view of completed environmental mitigation work in December of 2018. on Plum Creek looking toward Chatfield Reservoir.
In June of 2018, CRMC entered into a contract with CEI to construct the South Platte Environmental Mitigation Project, located upstream of Chatfield Reservoir. The project involved significant regrading and stabilization work along Upper Titan Lake to repair damage caused by the 2015 flood. The project also involved stream restoration along Willow Creek, plus regrading and stabilization work along the South Oxbow and Cigar Lake. The project also included a significant revegetation effort, involving the installation of more than 34,000 native potted plants, shrubs, and trees. Work commenced in July of 2018 and was completed in July 2019. Revegetation efforts within the area are ongoing.
The Season 1 activities (November 2017 –September 2018) included work on the North Boat Ramp, Massey Draw, Eagle Cove, Balloon Launch/Deer Creek, Swim Beach, Jamison, Catfish Flats, and Fox Run day use areas, plus Deer Creek Crossing, and a portion of the Perimeter Road stretching from Fox Run north to Eagle Cove. The North Boat Ramp, Massey Draw, Eagle Cove, Deer Creek, Balloon Launch, and Jamison day use areas were completed in 2018, as well as the Perimeter Road from Fox Run north to Eagle Cove. The Season 2 Aerial view of completed North Boat Ramp project. activities (September 2018 – August 2019) included the Swim Beach, Catfish Flats, Fox Run, Gravel Ponds, Kingfisher, Roxborough Cove and Plum Creek day use areas, the South Platte Bridge, Marina landside, Marina docks, Marina floating building, and the Perimeter Road, east and west of the South Platte Bridge. Additionally, Season 2 work includes Denver Water Pump Station relocation near the Fox Run day use area and the revegetation of Borrow Areas 3 and 5. The improvements summarized were completed in 2019.
All CSRP required construction has been completed, and all areas of the park are open (Figure 16).
2019 Annual Report Page | 15 Figure 16. CRSP Construction Map.
2019 Annual Report Page | 16 Wastewater treatment plants
Table 1 summarizes the wastewater treatment plants (WWTPs) in the Chatfield watershed and their respective TP wasteload allocations. In 2019, the total reported TP discharges from WWTPs were approximately 2,757 pounds out of the allowable wasteload allocation of 7,533 pounds. Refer to Figure 17 for WWTP locations. As growth in the watershed continues, wasteloads from the wastewater treatments plants will continue to rise towards the total allowed wasteload allocations.
Wastewater providers treat effluent to meet TP load allocations and a TP concentration pursuant to Control Regulation No. 73. The monitoring and reporting of effluent discharges demonstrate compliance with their individual permits and the state regulations. During 2019, the discharges maintained their record of compliance, with every discharger in the Chatfield Watershed complying with their TP concentration limits and TP wasteload allocation.
Table 1 - 2019 Phosphorus Wasteload from WWTPs in the Chatfield Watershed
TP Wasteload 2019 TP CDPHE Permit Permittee Allocation Loading Number (Pounds) (Pounds)
Plum Creek Water Reclamation Authority CO0038547 4,256 2,533
Perry Park Water and Sanitation District CO0022551 365 147.9
Perry Park Water and Sanitation District CO0043044 73 43.3
Lockheed Martin Space Systems Company CO0001511 1,005 21.1
Town of Larkspur COX632051 231 11.6
Highlands Ranch Law Enforcement Academy N/A 301 No Discharge4
Centennial Water and Sanitation District CO0037966 20 0
Ponderosa Retreat and Conference Center COX047511 752 No Discharge5
Louviers Water and Sanitation District COX632098 122 No Discharge6
Dominion Water and Sanitation District CO0041645 1,218 No Discharge6
Sacred Heart Retreat COX041874 153 0.27 No Data Jackson Creek Ranch N/A 50 Available Reserve Emergency Pool N/A 73 Not used
TOTAL PHOSPHORUS WASTELOADS 7,533 2757.17
Notes: *TP loading from WWTPs is from the WWTP point of discharge; the TP load discharged from WWTPs does not equate to the TP load delivered to Reservoir due to assimilation of TP and geochemical fate and transport processes in the watershed. 1. Law Enforcement Foundation water quality credits awarded pursuant to Authority’s Trading Program. 2. Ponderosa Retreat Center water quality credits are subject to completing a trade project pursuant to the Authority Trading Program. 3, Temporary five-year phosphorus allocation of 15 pounds for inclusion in discharge permit; allocation obtained from Dominion Water and Sanitation District. 4. Wastewater reuse is authorized under Regulation 84 – Reclaimed water, with not discharge. 5. Source: Environmental Protection Agency Integrated Compliance Information System database.
2019 Annual Report Page | 17 6. No discharge of wastewater effluent reported in the Chatfield watershed. Figure 17. Wastewater Treatment Plants located within the Chatfield watershed.
2019 Annual Report Page | 18
Site location applications As the 208 Management Agency, the Authority reviews site location applications and associated engineering reports for new or proposed facilities to effectively manage waste treatment works and related facilities serving Chatfield Basin.
The Authority reviews, comments, and makes recommendations to the Water Quality Control Division for site location applications for domestic wastewater treatment works, including wastewater treatment plants, individual sewage disposal systems, lift (pumping) stations, and certain interceptor sewers with a capacity of 2,000 gallons per day or greater, as well as certain facilities that produce reclaimed domestic wastewater. As required by Colorado’s Site Location and Design Approval Regulations for Domestic Wastewater Treatment Works (Regulation 22), most site location applications are submitted to the Authority by the Applicant prior to submittal to the Water Quality Control Division.
Under Control Regulation No. 73, the Authority is to implement the TMAL for total phosphorus loading to the Reservoir. The Authority reviews site location applications for compliance with the Control Regulation No. 73 and the Emergency Response Plan. The review primarily assesses the following criteria:
Colorado Department of Public Health and Environment (CDPHE) WQCC Control Regulation No. 73: 73.3.2(b): “No municipal, domestic, or industrial wastewater discharge in the Chatfield Watershed shall exceed 1.0 mg/L total phosphorus as a 30-day average concentration, except as provided under section 73.3(2)(f).”
CDPHE WQCC Control Regulation No. 73, 73.3.2(c): “The allowed annual wasteload of point source phosphorus in the Chatfield watershed is limited to 7,533 lb/year, allocated among the dischargers.”
The likelihood of sanitary sewer overflows and contaminants reaching Chatfield Reservoir, Plum Creek, or the South Platte River and, in the event of an emergency, the ability of emergency response plans to contain the sanitary sewer overflows and contaminants, per the Cherry Creek Reservoir Watershed Site Application Review Process Emergency Response Plan Criteria (Emergency Response Plan Criteria) which have also been adopted by the Chatfield Watershed Authority. applications reviewed In 2019, the Authority reviewed the following project for compliance with the Chatfield Reservoir Control Regulation No. 73:
Jellystone RV Park at Larkspur
Project Summary: Site Application for a Wastewater Lift Station, a Wastewater Treatment Facility (0.044 mgd design capacity), and a Phosphorus Non-Point Source to Point Source Trade Application (145.2 lbs/yr current septic system to 72.6 lbs/yr, with the WWTF discharging to groundwater).
The Chatfield Watershed Authority was formed by local governments and Title 32 districts, industry, corporations, and other entities within the Chatfield Watershed to implement point source, nonpoint source, and/or stormwater controls. - Control Regulation No. 73.2.4
2019 Annual Report Page | 19 Findings: The removal of the existing septic systems was computed to result in a reduction of phosphorus entering the groundwater system of about 145.2 lbs/yr. This quantity of phosphorus is based upon assumptions of historical loadings and phosphorus concentrations and not complete site-specific data. Additional data from another RV campground and technical literature was provided to collaborate this assumption.
The amount of phosphorus discharged to East Plum Creek is estimated to be 40% of that discharged into the groundwater system at the leach field. This same estimate applies to the proposed groundwater disposal. This estimate does not affect the current proposed trade but would affect the amount of trade credit if this were to become a surface discharge facility.
The minimum required 2:1 trade ratio requires the WWTF to discharge no more than 72.6 lbs/yr of phosphorus. At full design capacity, the 72.6 lbs/yr limit results in a phosphorus discharge concentration of 0.5 mg/l. The WWTF is designed to meet this phosphorus concentration limit.
Recommendation: The Authority took action to approve the proposed nonpoint source (145.2 lbs/yr) to point source (72.6 lbs/yr) phosphorus trade with the following conditions:
1. Certification by the project engineer and owner that the existing septic systems will be removed and will no longer be functional within 60 days after the WWTF goes online.
2. Written verification from Tri-County Health Department that the existing septic systems have been properly decommissioned, and their permits revoked within 60 days after the WWTF begins discharging to the effluent pond.
3. 30 days prior to a final action by the Colorado Division of Public Health and Environment (CDPHE) on the proposed phosphorus trade, a report signed by a Colorado Professional Engineer shall be provided to the Authority for review and comment to CDPHE, that states that the site conditions at the proposed effluent pond will allow for the continuous disposal of treated effluent at a minimum rate of 0.044 mgd into the groundwater table for a period of at least five (5) years. The report shall also state what level of maintenance is necessary to meet this requirement. The report shall also include the engineer’s opinion whether the engineer expects the infiltrated effluent will remain as groundwater before surfacing at East Plum Creek. This report shall include soil borings and analysis sufficient to support the engineer’s conclusions. The applicant shall agree to implement the maintenance requirements stated in this report.
4. The applicant shall propose a monitoring plan for review and approval by the Authority that will provide proof over time that the operation of the effluent pond doesn’t result in a surface water discharge of the pond effluent before such effluent reaches Plum Creek.
5. The applicant shall state in writing that they understand and will abide by the requirements of “Section VIII(C) Adjustments and Revocations” of the Authority Trading Guidelines.
6. The applicant shall monitor the phosphorus concentration of the WWTF influent and provide a yearly report to the Authority (by January 31 of each year) providing the monitoring results and calculating the average WWTF influent phosphorus concentration for that year and the total phosphorus influent load based upon the flow rates used for the original credit calculation. This information may be used to revise the phosphorus credits based upon the provisions of “Section VIII(C) Adjustments and Revocations” of the Guidelines.
The Authority recommended that the Division consider approving the proposed nonpoint to point source trade as specified with the conditions presented above.
2019 Annual Report Page | 20
Regulated stormwater sources Colorado’s stormwater permit program requires control of stormwater runoff in all Phase I and Phase II Municipal Separate Storm Sewer Systems (MS4) entities. These requirements are separate and distinct from the Chatfield Control Regulations and complement the TMAL’s purpose. Through the efforts of the MS4s, rate payers have spent significant funds to address water quality through implementing projects to mitigate impacts from urban stormwater runoff. Authority members with Phase I and II MS4 permits in the Chatfield Basin include:
Statewide General Permit (COR090000) Jefferson County City of Littleton Cherry Creek Reservoir General Permit (COR080000) Douglas County City of Castle Pines Town of Castle Rock Individual / Other Permit Castle Pines Metropolitan District Colorado Department of Transportation Non-Standard General Permit (COR070000)
General MS4 permits require the permittee to develop programs that meet six minimum control measures:
Public education and outreach on stormwater impacts
Public participation and involvement
Detection and elimination of illicit connections and discharges
Construction site stormwater runoff control
Post-construction stormwater management in development and redevelopment
Pollution prevention/good housekeeping for municipal operations
MS4 permits require implementation of best management practices (BMPs) to reduce pollutants discharged to the “maximum extent practicable.” A summary of 2019 MS4 permit inspection and enforcement metrics are provided in Table 3.
2019 Annual Report Page | 21
Table 3 – Summary of 2019 MS4 Permit Activities
Permit Inspection Actions Permit Enforcement Actions
ction
Discharges
Construction Construction
- -
Illicit Illicit Discharges Post Construction Post Land Use Agency Permit Number Constru
Douglas County COR080003 8 6,555 36 0 161 0 Jefferson County COR090024 32 687 38 32 28 0 Town of Castle Rock COR080012 0 3.569 88 0 57 0 City of Littleton COR090055 4 171 20 0 3 0
Notes:
Castle Pines Metropolitan District inspection and enforcement action data are incorporated in Douglas County reporting; City of Castle Pines MS4 boundary is predominately in the Cherry Creek Basin; only a very small portion is located in the Chatfield Watershed.
Town of Castle Rock inspection and enforcement action data includes data from the Cherry Creek Basin and the Chatfield Watershed. Town of Castle Rock MS4 boundary is predominately in the Chatfield Basin; about two-thirds of the Town is located in the Chatfield Watershed.
The data for the City of Littleton includes all MS4 activities within the city limits. However, the city limits of Littleton only overlap with the Chatfield watershed boundary for a small portion (i.e. the Trailmark development)
2019 Annual Report Page | 22 Education and outreach Douglas County Douglas County’s Stormwater Management Program provides public education, tracking of stormwater system impact activities, stormwater system project reviews, and coordination between federal, state, and local government for compliance with federally-mandated programs.
Through a county Co-op program, the county has created the “One Thing is Clear… our creeks, rivers and lakes depend on you” public awareness program. The interactive website provides information for Douglas County residents on how they can work to keep pollution out of their water ways. CLEAR Members collaborated with Members of Stormwater Permittees for Local Awareness of Stream Health (SPLASH) on Nutrient Outreach and training seminars.
Douglas County completed the following activities in 2019:
Maintained a portable “Road Show” for members to use as an Education and Outreach tool with the public.
Maintained the CLEAR website at http://onethingisclear.org/
Ran a total of 120 two-third page residential and commercial awareness advertisements (12 ads in 10 publications) monthly in Colorado Community Media newspapers covering certain portions of Douglas, Arapahoe, Jefferson and Elbert Counties. Ads ran in the Castle Rock News Press, Castle Pines News Press, Douglas County News Press, Lone Tree Voice, Highlands Ranch Herald, Centennial Citizen, Englewood Herald, Littleton Independent, South Platte Independent, Parker Chronicle and Elbert County News.
Held five (5) membership meetings to discuss the stormwater topics of the day and maintain an organized discussion on the interpretation and application of federal and state stormwater regulations. All meetings are open to the public with the opportunity to comment.
Members supported three (3) Tri-County Health Department/Douglas County Household Chemical Roundups.
Members supported and attended both general and committee meetings of the Colorado Stormwater Council. Members supported the Cherry Creek Stewardship Partnership and attended their annual conference.
Members actively participated and commented on the Non-Standard MS4 “Draft” Permit.
Additional information on various topics related to Stormwater and Pollution Control can be found on Douglas County’s website.
2019 Annual Report Page | 23 Town of castle rock The Town of Castle Rock (Town) is currently completing minor drainageway improvements. The original storm sewer systems constructed within portions of the Woodlands subdivision and along Canyon Drive and in Rock Park do not extend all the way to their respective drainageways (Hangmans Gulch Tributary B and Parkview Tributary). As a result, significant erosion has occurred that if left unaddressed will eventually impact private residential lots in the Woodlands, as well as public infrastructure (Canyon Drive). This project will correct these issues by extending the existing storm sewer outfalls to their respective drainageway channels, and then backfilling and replanting the eroded areas with native grasses. Additionally, the most severe areas of stream bank erosion will be repaired using soil lifts to minimize disturbance of the existing vegetation while preventing further damage from occurring. Construction began in December of 2019 and is currently on schedule for completion in the Spring of 2020.
Spring Up the Creek has become a tradition for Castle Rock and draws residents every year to preserve our waterways by removing trash that collects along the stream banks. Held on Saturday, May 4, 2019 and playing off the theme, May the Forth Be With You day, the theme was “Be a Force for Nature.”
The Town had 178 volunteers and picked up 89 bags of trash. The event was headquartered at Festival Park and participants either walked or were shuttled to seven locations throughout town.
The Town of Castle Rock hosted this event in partnership with Douglas County, Castle Pines Metro District, Chatfield Watershed Authority, and Plum Creek Water Reclamation Authority. Through these sponsorships, the partners were able to offer breakfast, gloves and trash bags for the clean-up, kids’ activities and commemorative t-shirts to volunteers, free of charge. jefferson County Jefferson County (County) regularly reports to the Chatfield Watershed Authority on stormwater management. The county has a municipal separate storm sewer (MS4) permit management program that includes:
Public Education and Outreach
Public Participation and Involvement
Illicit Discharge Detection and Elimination
Construction Site Runoff Control
Post Construction Site Runoff Control
Pollution Prevention/ Good Housekeeping
The county provides opportunities for residents and visitors in the watershed to learn and be involved in environmental stewardship and programs that promote water quality. The county has a comprehensive storm 2019 Annual Report Page | 24 sewer outfall map to trace sources of potential illicit discharges and illegal dumping in the watershed. Jefferson County continues to participate with Rooney Road Recycling Facility and in 2019 the facility collected over 530,000 pounds of household hazardous waste. Household hazardous waste (includes electronic waste, household chemicals, paints, propane cylinders and automotive products) materials collected at the Rooney Road Recycling facility since 1994 total more than 7,500,000 pounds of potential surface water and ground water pollutants. This process keeps materials out of septic systems and helps reduce illegal dumping in the watershed. Jefferson County participated in a number of public events to reach diverse audiences for their MS4 and floodplain management programs.
Jefferson County regularly reports to the Authority on stormwater management practices and programs. More information about Jefferson County’s municipal stormwater program is contained in their CDPS Stormwater Permit Annual Report.
City of littleton
In 2019 the City of Littleton (City) worked closely with the Trailmark Metro District to maintain a water quality pond to ensure continued functionality. Additionally, City staff conducted stream cleanups, storm inlet marking, and water quality educational outreach to schools, in the City newspaper, and through social media sites.
The City of Littleton provided water quality protection information at the summer Meet, Greet & Eat events, four of which are held each summer in rotating locations; some years these are in Trailmark. The outreach is related to nutrient reduction, pet waste and fertilizer/grass clippings management. The City also participates in a regional stormwater group’s information booth at Western Welcome Week in downtown Littleton.
2019 Annual Report Page | 25 Progress to promote water quality protection
While funding sources remain very limited, the Authority’s collaborative role seeks out partnerships to support our water quality goals now and in the future. Donations and in-kind services from Authority members to support progress to promote water quality protection included:
Continued implementation of the amended Intergovernmental Agreement (IGA) and bylaws
Continued water quality monitoring program in both the reservoir and the watershed.
Continued implementation of the Chatfield Watershed Plan
Continued collaboration with Chatfield Reservoir Mitigation Company (CRMC) regarding data collection to support CRMC reservoir modeling efforts
Continued Public Outreach Committee activities
2019 Annual Report Page | 26 Chatfield Watershed Authority Members www.chatfieldwatershedauthority.org
Members consist of water and sanitation districts, water providers, municipalities, metropolitan districts and other area stakeholders within the Chatfield Watershed. The membership representation consists of organization staff and elected officials. Membership dues assist with collaborative projects and water quality testing.
Chatfield watershed authority Members City of Littleton Denver Water Douglas County Jefferson County Roxborough Water & Sanitation District Town of Castle Rock Perry Park Water & Sanitation District Centennial Water & Sanitation District Town of Larkspur Castle Pines Metropolitan District Dominion Water & Sanitation District Louviers Water & Sanitation District Plum Creek Water Reclamation Authority
Ex-Officio Participants Colorado Agricultural Leadership Foundation (CALF) Colorado Parks and Wildlife Commission (Chatfield State Park) Colorado Department of Transportation Colorado Water Conservation Board Ken Caryl Ranch Master Association The Law Enforcement Foundation Ponderosa Retreat Sacred Heart Retreat Tri-County Health Department U.S. Army Corps of Engineers Chatfield Reservoir Mitigation Company Water Quality Control Division of Colorado Department of Public Health and Environment
Watershed Manager Colorado Watershed Assembly
Website Hughes and Stuart Sustainable Marketing
Financials TWS Financial, Inc.
Technical consultant RESPEC Company, LLC
2019 Annual Report Page | 27
2019 Annual Report Page | 28