Jackson Creek Beneficial Use Assessment Pool Refugia Study
Author Information
Kimberly Smith
American River College, Geography 350: Data Acquisition in GIS; Fall 2008
Smith.KimberlyS@gmail.com
Abstract
The City of Jackson conducted a Beneficial Use Assessment in compliance with the Special Conditions of the City’s Wastewater Treatment Plant NPDES permit for surface water discharges to Jackson Creek. The purpose of the study was to assess whether under current conditions Jackson Creek is meeting specified biological beneficial uses and to determine the creek flows necessary to meet existing water rights allotments along the creek below the outfall. The study was aimed at determining whether the City can comply with the Department of Health Service’s policy and stay out of the creek when the effluent content of Lake Amador exceeds 20% (as a monthly average) and yet still meet the existing wildlife, fisheries (protected under California Department of Fish and Game Code), and water rights demands (protected under the California Water Code). The Surface Water Ambient Monitoring Program Protocol was utilized at four sites (2 above the outfall and 2 below) to assess the existing biological conditions of the creek. In addition, a water quality and temperature study, pool habitat assessment, and targeted amphibian surveys were conducted. Existing documented water rights were searched and assessed through State Board databases. After the afore mention studies were conducted, the City, Fish and Game, and the State Water Resources Control Board (SWRCB) determined that further information on pool refugia was needed to determine if sufficient habitat would be present in dry conditions for critical species.
The Creek below the outfall exhibits a dense riparian habitat dominated by cottonwood, alders, ash, and willows. Warm water fish (green sunfish and pikeminow) were encountered below the outfall and warm and cold water fish (green sunfish, pikeminow, rainbow trout, and brown trout) were documented above the outfall. There is however a large barrier (40 foot dam) between Lake Amador and the outfall, therefore fish are not migrating up from the Lake and are more likely supplied from lakes in the upper watershed. The creek does support wildlife. Four amphibian species (including one State species of special concern) were encountered in the creek. Two reptiles (including one State species of special concern) were encountered above and below the outfall. In addition, the aquatic dependant common mammal species, the river otter was also encountered. Multiple terrestrial species such as black tailed deer, raccoons, and wild cats also likely frequent the creek for water. Based on the pool refugia assessment the City was able to determine there are at least 50 pools downstream of the WWTP. Therefore, based on our study, Jackson Creek below the outfall currently supports warm water fisheries and aquatic-dependent and -associated species. During the summer months the creek may not support cold water fisheries; however, because they exist upstream, it is likely that during winter months cold water fisheries are present below the WWTP.
Downstream of the Jackson WWTP there are nine riparian water rights holders. According to the SWRCB there is only one agency with appropriative water rights downstream of the Jackson WWTP, the Jackson Valley Irrigation District (JVID). The JVID have two appropriative permits. There are no records of pre-1914 water rights on Jackson creek downstream of the Jackson WWTP.
Based on our examination of Jackson Creek riparian habitat, water rights, natural water flows, and beneficial uses removing the treated wastewater from Jackson Creek appears to be beneficial to human health and continue to meet the beneficial uses of the watershed. Therefore, based on our study we believe the City of Jackson should be allowed to consider alternatives methods of wastewater disposal.
Introduction
On October 25, 2007 the Central Valley Regional Water Resources Control Board (RWQCB) adopted waste discharge requirements for the City of Jackson Waste Water Treatment Plant (WWTP) via Nation Pollution Discharge Elimination System (NPDES) permit No. CA0079391 and Order No. R5-20070133. The Special Provisions of the NPDES permit required the City to conduct a Beneficial Use Assessment Study (BUAS) to assess the existing biological and water rights conditions below the WWTP.
The BUAS requirement in the NPDES permit is the result of two conflicting agency concerns. Specifically, the Department of Health Services is concerned about the effluent dominated Jackson Creek flow (during summer months) leading to a less than 20% dilution ratio in the Lake Amador drinking water. Therefore, DHS would like the City to either reduce or eliminate the effluent in the creek. In contrast, California Department of Fish and Game staff has expressed concern about public trust fisheries and wildlife that are (and have been for the past 30 years) dependent on the City’s effluent for habitat during summer months. In addition the State Water Resources Control Board (SWRCB) oversees water rights and must ensure adherence to all existing water rights.
Therefore, the purpose of this study was to assess if under current conditions Jackson Creek is meeting specified biological beneficial uses including: warm freshwater aquatic habitat, cold freshwater aquatic habitat, warm and cold fish migration habitat, warm spawning habitat, wildlife habitat, and navigation and to determine if the Creek will continue to meet the beneficial uses if all wastewater is removed. In order to determine if beneficial uses are met in Jackson Creek the pool refugia data will be used to clarify that sufficient habitat is present to support sensitive species if the City were to remove all the effluent.
Background
The City of Jackson (City) Wastewater Treatment Plant (WWTP) was built approximately 50 years ago and provides treatment services to the City’s 3,989 residents and (12 to 15,000 vacation residents) (Figure 1- Vicinity Map) The WWTP is an ‘Advanced secondary WWTP’, with a system that consists of a mechanical screen and spiral augur with a washer compactor for screenings, two oxidation ditches (only one is used at a time), two secondary clarifiers (only one is used during the summer, both are used during the winter months), chlorine injection, one train of four single media sand filters, chlorine contact basins, and dechlorination. Solids are directed to an aerated holding tank for digestion, and then directed to a belt filter press. Solids are hauled off-site to a landfill for disposal. Wastewater is discharged to Jackson Creek, a water of the United States, and a tributary to Lake Amador within the Mokelumne River watershed.
The State Water Resources Control Board (SWRCB) regulates the City’s WWTP discharge by use of the National Pollution Discharge Elimination System (NPDES) permit program. Which was established under the Clean Water Act and it regulates and gives permits to discharges of pollutants from a point source (pipe, ditch, well, etc.) to United States waters. The NPDES permit establishes allowable discharge limits or effluent limitations that include both concentration and volume of flow. Permittees are required to verify compliance with permit requirements by monitoring their effluent, maintaining records, and filing periodic reports.
The City of Jackson’s Permit (No. CA0079391) requires the City to meet 20:1 dilution standards about 7 miles downstream of the WWTP at Lake Amador. The permit also requires the City to conduct a study determining the acceptable amount of water to maintain biological habitat and meet dilution requirements.
The California Department of Fish and Game (CDFG) is the regulatory agency that over sees the protection and management of California’s diverse fish, wildlife, and plant resources, and the habitats upon which they depend, for their ecological values and for their use and enjoyment by the public. The Department has no officially adopted regulations or statutes pertaining to wetlands or creek areas. However, Fish and Game Code §1601 and §1603 charge DFG with executing Streambed Alteration Agreements. Fish and Game Codes §§5650-5645 pertain to the protection of water quality but do not charge DFG with additional permitting responsibilities. As designated a Trustee and/or Responsible Agency per the California Environmental Quality Act §15386 and §15381, DFG reviews and comments on documents produced by the lead agencies. DFG also administers the California Endangered Species Act and “lists plant and animal species per the act (CDFG). CDFG will not advise the SWRCB to grant the water rights application permit under their CEQA review if sufficient evidence is not presented that beneficial uses within Jackson Creek will be maintained if and when all the effluent is removed from the Creek.
The Department of Health Services (DHS) is the regulatory agency that over sees the protection of the health and well-being of the people in California. DHS wants to ensure that the water in Lake Amador is maintained below the 5% effluent limit to ensure the safety of the public in the Jackson Valley whom receive their drinking water from Lake Amador (DHS).
Project Area and Setting
The Jackson creek watershed is located in Sierra Nevada foothills, Amador County, California within the Mokelumne River watershed. Jackson Creek is fed by three main tributaries that converge at their confluence within at the City and create a single main stem Jackson Creek that flows west from the City past the WWTP to Lake Amador. The capacity of Lake Amador is 22,000 acre-feet. Beyond Lake Amador, Jackson Creek flows west to Dry Creek and eventually to the Mokulumne and the San Joaquin River.
The landscape along Jackson creek varies from black oak/mixed coniferous forest in the upper reaches above the City of Jackson. Below the City and the WWTP (Figure 1) the terrain surrounding the creek consists of rolling hills and some steeper canyon walls banks dominated by annual grasses and interior live and blue oak woodland. With the exception of some urbanized areas above the WWTP and some grazed areas below the plant, almost the entire creek is lined by a relatively dense riparian zone of predominantly alders and Oregon ash with interspersed cottonwoods.
Jackson Creek has a temperate climate with warm to hot summers and moderate to cold winters. The average annual rainfall is 29 inches and the average annual snowfall is 1 inch. The average annual rainfall for the City is 30.94 inches (Idecide). The spring of 2008, the year of this study, was the driest spring on record (DWR). In addition, this current two year period is the 9th driest period on record (DWR). The lowered annual rainfall is evidence of a dry year within a generally temperate climate.
Jackson Creek is a foothill stream with a watershed area of about 60 square miles and a maximum watershed elevation of less than 3000 feet (above mean sea level). Streams in the Jackson Creek watershed are perennial streams, that is, streams whose channels contain some flowing water year round. The headwaters of the middle fork of Jackson creek are located near the town of Pine Grove off of highway 88. The south fork of Jackson Creek is also located at a similar elevation to Pine Grove but located south of Pine Grove and north of the Mokelumne River. Winter, spring, and summer flows are primarily a result of rainfall, and rainfall recharged shallow groundwater. Late summer and autumn flows are believed to contain substantial amounts of water imported into the Jackson Creek watershed by the Amador Water Agency (AWA) for municipal, domestic, and agricultural uses. For years, leakage from old unlined water conveyance ditches has been a source of dry season water to Jackson Creek. This source will be disappearing as the old ditches are replaced with pipelines to reduce water losses. With the loss of ditch leakage, Jackson Creek upstream of the City should return to a more natural state with even less flow in late summer and autumn.
Prior to conducting fieldwork, ECOLOGIC biologists conducted a site screening using the California Natural Diversity Database (CDFG). Nine special status species were identified; however, the majority of the species are associated with Ione Chaparral, which is not water dependent and not associated with creek habitats. The key special-status species expected to occur in the area based on CNDDB data and the known foothill habitats found around the creek include western pond turtle, foothill yellow-legged frog, California red-legged frog, and valley elderberry beetle.
Main Objectives
The purpose of this study is to augment our site-specific understanding of potential fish, amphibian, and western pond turtle refugia for a dry year, late summer, and no flow conditions. The goal is to document the amount of available pool habitat and the quality of that habitat downstream of the City’s discharge to assist in assist the team in analysis of discharges to the creek in the future. For the purpose of this study and in accordance with SWAMP, pools are defined as areas with reduced flow velocity and depths greater than ˝ meter. Pool habitats will be mapped using GPS and GIS techniques to provide a visual representation of the area.
Figure 3 Reach Selection and Water Quality Monitoring Sites.
Methods
The field data was collected on November 10, 2008 ECO:LOGIC staff conducted field surveys to map the pools within the 4.1 mile stretch of Jackson Creek between the Jackson Wastewater Treatment Plant and Stony Creek Bridge. The field team consisted of: An aquatic biologist, an amphibian/aquatic insect specialist, and a field biologist who conducted the SWAMP geomorphology data collection.
A three person field team was vital to ensure data was collected efficiently at each pool and maximized the stream length covered in this single day survey. The amphibian specialist walked the thalweg measuring stream depths and documenting amphibian habitat. The aquatic biologist assessed fisheries habitat and riparian cover and record all team data. The field biologist will estimate pool lengths and widths, collect all GPS data and photo document all pools/potential refugia.
The crew began the survey at 8:30 am at the Wastewater Treatment Plant and worked their way downstream to Stony Creek Bridge where the survey was finished at 5:30 pm. The weather was cool and clear throughout the survey. The survey was conducted at the end of the dry season after the first rain of the year. Spatial data was gathered using Trimble and Garmin Etrex Vista C GPS units. The following pool habitat assessment data was collected along the study reach: Pool Depth -Thalweg depths (including Max Depth) were measured with a Meter Stick and averaged (minimum of 3 depths per pool).
•Pool Length – Estimated based on single person paces and verified with a digital view finder.
•Pool Width – Visual Estimate using meter stick.
•Canopy Cover – Visual estimate of percent cover by quadrille
•In-stream Substrate Type - (fines, gravel, cobble, boulder, bedrock).
•Dominant In-stream Fisheries Cover Type and Estimated Percent: Woody debris and undercut banks.
•Emergent Vegetation Cover- Estimated percent.
•Basking Habitat – Presence and Type.
•Species observed – Notes on aquatic or water dependant species observed during survey.
•GPS Data Point – Collected at base (downstream end) of pool in accordance with SWAMP nomenclature.
•Photo –photo of each Pool facing upstream.
In addition, springs and other surface water inputs noted during the stream survey were GPS documented. In-stream temperature gauges were collected, the data was downloaded, and gauges replaced at the five temperature monitoring sites.
Results
The study area began at an elevation of 1100 feet at the WWTP and the surroundings creek conditions included moderate depths with some deep pools and large amounts of algae growth due to the site’s close proximity to the WWTP outfall. The study area was characterized by areas of smaller substrate but mainly bedrock confined pools.
Photo 6 View of each reach looking downstream.
The field survey documented 60 pools between the wastewater treatment plant and the Stony Creek Road Bridge. Pools were divided into three size classes as small, medium, and large. Of the 60 pools five fell into the large category, 30 into the medium category, and 25 into the small category. Large pools consisted of all pools with a depth greater than 3 meters, medium pools ranged from 2-3 meters, and small pools were marked between 1 and 2 meters.
Using Expert GPS and ArcView, I was able to put together a map of the pool and tribuatary locations.
Figure 4 Pool Refugia Data- any pool over a meter deep.
Water quality studies of the creek indicated that the range of temperature in Jackson Creek ranges 58 and 78 degrees Fahrenheit over the 12 month period the Creek was studied. Temperatures varied slightly between the upstream and downstream reaches with an anomaly on the Busi property since it was on average 5 degrees warm than either upstream site and warmer than the other downstream site Stony Creek Bridge.
Site
Minimum (Degrees F)
Maximum (Degrees F)
Average (Degrees F)
Standard Deviation (Degrees F)
1
62.70
92.24
67.03
2.55
2
64.93
80.05
71.94
3.02
3
59.14
72.99
65.01
2.89
4
53.47
86.98
65.83
3.73
*Temperatures are based on continuous data loggers logging every 15 minutes.
Daily Average Temperature Data During Hottest Summer Months (June – August, 2008)
Figure 5 Daily Average Water Temperatures above and below the WWTF discharge site in Jackson Creek (Red tones = below and Blue tones = above the WWTF).
The Creek below the outfall exhibits a dense riparian habitat dominated by cottonwood, alders, ash, and willows. Warm water fish (green sunfish and pikeminow) were encountered below the outfall and warm and cold water fish (green sunfish, pikeminow, rainbow trout, and brown trout) were documented above the outfall. There is however a large barrier (40 foot dam) between Lake Amador and the outfall, therefore fish are not migrating up from the Lake and are more likely supplied from lakes in the upper watershed. The creek does support wildlife. Four amphibian species (including one State species of special concern) were encountered in the creek. Two reptiles (including one State species of special concern) were encountered above and below the outfall. In addition, the aquatic dependant common mammal species, the river otter was also encountered. Multiple terrestrial species such as black tailed deer, raccoons, and wild cats also likely frequent the creek for water.
Riparian cover
Figure 6 Riparian cover (with standard error bars) at each site as measured with a densitometer along the stream centerline. Averages taken from 11 transects per site.
Downstream of the Jackson WWTP there are nine riparian water rights holders. According to the SWRCB there is only one agency with appropriative water rights downstream of the Jackson WWTP, the Jackson Valley Irrigation District (JVID). The JVID have two appropriative permits. There are no records of pre-1914 water rights on Jackson creek downstream of the Jackson WWTP.
Figure 7 Water Rights holders along Jackson Creek.
Analysis
After careful examination of the data, it was deduced that of the large pools all five would provide suitable habitat for species of concern. Meanwhile, only 20 of the 30 medium sized pools would provide suitable habitat due to not meeting minimum volume requirements. Finally, 15 of the small sized pools met criteria to provide suitable refugia. Therefore, according to SWAMP standards, CDFG, and the City 75% of the pools existent downstream of the WWTP meet the depth and volume criterion to be considered suitable habitat in dry conditions for western pond turtle and foothill yellow legged-frog (and other potentially sensitive species).
Based on the results of the water quality study, the City was able to ascertain that the water quality in the Creek is reasonably healthy upstream and downstream of the WWTP. The range of temperatures indicates that the Creek meets its warm water fisheries/habitat designation. The presence of trout in the upstream reaches of the Creek indicate that cold water fisheries are most likely met upstream; however, by some natural barrier (i.e. the WWTP or the City itself) it does not appear that cold water fisheries are present downstream, despite the cooler temperatures at Stony Creek Bridge.
Therefore, based on our study, Jackson Creek below the outfall currently supports warm water fisheries and aquatic-dependent and -associated species. During the summer months the creek may not support cold water fisheries; however, because they exist upstream, it is likely that during winter months cold water fisheries are present below the WWTP.
pool and habitat analysis was executed fairly successfully. The team of biologists was able to go out and survey the Creek from the outfall downstream to Stony Creek Bridge without anyone getting hurt and with enough time to collect data on the entire reach. However, a few minor problems did arise. First, when the team reached the treatment plant they realized the Trimble GPS unit had a dead battery despite charging it over night. Luckily the team had brought a backup Garmin etrex, which was easy to carry and use.
In the future, it is recommended that a specific detailed work plan is derived before fieldwork begins, ensuring efficiency and production of quality data that is focused on the correct issues.
Conclusion
Once the City determined that suitable pool refugia was present downstream of the WWTP, they were able to present their data to DHS, CDFG, and SWRCB and recommend the solution of removing the wastewater from Jackson Creek to meet public health standards without jeopardizing the health of the wildlife in and around the Creek.
Several engineering options have been presented to the City to provide alternate methods of wastewater disposal. The most heavily weighted idea is to build a regional treatment plant in Martell (a City just to the North of Jackson on Highway 49) just like the Sacramento Regional Treatment Facility in Elk Grove. Other options include land disposal or giving the water to local ranchers. At this time, the City has not made a decision on how to approach complying with their NPDES permit.
If the City does remove the wastewater from Jackson Creek, Fish and Game will require three years of Creek monitoring, providing status and health updates on water-dependant species and vegetation. The monitoring also provides Fish and Game an easy chance to study what returning creeks back to their natural conditions looks like in a real world situation.
It appears that many more Beneficial Use Assessments will be required from NPDES permits in the future as drinking water demands increase and drinking water supplies decrease. It will be a unique opportunity for the biological community to pull together and assess if returning a stream to its natural conditions is beneficial and if it is beneficial then what kind of wastewater disposal solutions are available?
Photo 8- Western Pond Turtle (special species
of concern) observed at all four sites.
References
CDFG. California Department of Fish and Game. Retrieved 2008, from State of California Government Pages: http://www.dfg.ca.gov
DHS. Department of Health Services. Retrieved 2008, from State of California Government Pages: http://www.dhs.ca.gov
DWR. Department of Water Resources. Retrieved 2008, from State of California Government Pages: http://www.dwr.ca.gov
Idecide. Weather. Retrieved December 2008, from Jackson Weather: http://www.idecide.com/weather/ca/jackson.htm
