Clark_Geologic_Report.pdf

GEOLOGIC REPORT

GROUNDWATER INVESTIGATION FOR FOREST SERVICE FACILITIES

CAMPGROUNDS AT CLARK SPRING, BUSHY TAIL, & MINERSVILLE PLUS MULE CREEK GUARD STATION

By: Juan de la Fuente, Northern Province Geologist: February 10, 2015

EXECUTIVE SUMMARY

There at least three viable options for developing groundwater at the Clark Spring, Bushy Tail, and

Minersville Campgrounds, and for the Forest Service Guard Station at Mule Creek. These include:

1. Drilling a Horizontal Well- The best prospect by far for drilling a horizontal well is immediately above the spring development at Clark Spring. The second best is on the NW edge of the paved parking lot at Clark Spring Campground. Two other optional sites are addressed below.

2. Drilling a Vertical Well- The best site for drilling a vertical well would be within the Clark Spring

Campground at one of the sites described in the body of the report (GPS locations 375, 383, 384, 396, 397 and 400 on Map 6). The second best would be the lower site at Bushy Tail

Campground at GPS location 372 on Map 6. Other potential sites are described below.

3. Reconstructing the Spring Box at Clark Spring- Reconstructing the spring box at Clark Spring would provide a backup to other systems, and it may be possible to do this at relatively low cost.

Each option has a unique set of pros and cons, including initial drilling and construction costs, linking to the existing system maintenance, upkeep, consultation with other agencies, and potential for contamination. Geologic factors relevant to each option are described below under the heading:

“Groundwater Development Options”.

PURPOSE AND BACKGROUND

The purpose of this investigation was to identify options for developing a groundwater supply for the

Clark Spring, Bushy Tail, and Minersville Campgrounds, and for the Forest Service Guard Station at Mule

Creek along Highway 3. Currently, these facilities receive water from a spring development (Clark

Spring), but during the summer of 2014, the system ceased to function. Though no longer supplying water to the distribution system, the spring continued to discharge water into a small channel below the spring box at a sustained rate of about 5 gallons per minute in late fall, 2014. Locations of the facilities at hand are displayed on Map 1. Methods used in this investigation included the following: a) Review of the Forest geologic data bases; b) Review of previous geologic investigations; c) Review of the USGS

Mines data base; d) Consultation with California Highway Department (Caltrans); e) Field reconnaissance.

Map 1- Location of Facilities

GEOLOGY AND GEOMORPHOLOGY

Bedrock-

The project area is located in the Eastern Klamath Belt of the Klamath Mountains, and is underlain by ultramafic, metavolcanic , and metasedimentary rock, along with younger sedimentary rock of the

Weaverville Formation. These rock units are displayed on Map 2. The purple map unit in the center is ultramafic rock, which is part of the Eastern Klamath Belt, Trinity Terrane, and consists of peridotite and serpentinite. Serpentinite often contains natural asbestos, and this mineral can be introduced into the air if ground disturbing activities are conducted under dry soil conditions. Once airborne, it can present a health hazard. The green/blue unit east of the ultramafic rock is the Copely Greenstone, which is part of the Eastern Klamath Redding Terrane (Devonian in age), and consists of metamorphosed volcanic rock. The brown unit in the east half of the map is the Bragdon Formation, consisting of metasedimentary rock, including shale greywacke, and minor conglomerate), which is within the Eastern

Klamath Redding Terrane and is of Devonian/Mississippian age. The tan-colored rock unit occupying most of the west half of the map is the Weaverville Formation. This rock is Tertiary in age, and overlies the older rocks of the Eastern Klamath Belt. It consists of unconsolidated gravels and conglomerates, Map 2- Bedrock and approximate locations of existing wells (parcel numbers); Purple polygon in center is ultramafic rock; Refer to the text for a description of the other rock units;

along with some alluvium and lacustrine deposits. Since this unit forms a mantle on the older rocks, wells drilled into it may encounter the underlying rock if drilled sufficiently deep.

Geomorphology-

Weathering is quite deep in much of the project area, resulting in the development of thick red soils.

Landslide deposits mantle much of the Weaverville Formation and also some of the older rocks. These deposits are shown as brown polygons on Map 3, and are often very hummocky, with prominent benches and older eroded scarps present. Active slumps and earthflows have been mapped in the area

(red polygons on Map 3) and two additional active landslides were identified during this investigation.

These are shown as dashed red polygons on Map 5. No activities are planned in the vicinity of the landslide near the Minersville Campground, but there is a potential for drilling a horizontal well at the active earthflow south of the Mule Creek Guard Station. Such an action would have a stabilizing effect on the landslide.

Map 3 Geomorphology- Brown - Landslide deposits; Red- Active landslides; Light Blue- Eroding hillslopes; Dark blue, Trinity Lake;

Groundwater-

Three main aquifer types occur in the project area. These include bedrock fracture zones in the older

Klamath Mountains rocks, permeable zones of sand and gravel in the Weaverville Formation, and permeable zones in landslide deposits. The regional groundwater table is likely controlled by the elevation of Trinity Lake. For reference, Bushy Tail Campground and the Mule Creek Guard Station are about 330 feet in elevation above the maximum lake elevation.

Potential for Groundwater Contamination-

Possible sources of groundwater contamination which should be considered in deciding on exact locations of new water facilities are described below. Highway 3 traverses the top of the project area, and spills of hazardous materials could occur there. Such spills have the potential to enter the groundwater system if some permeable conduit exists through the soil, such as an old well, mine, or permeable fractured rock. Potential conduits to groundwater include the following.

Old Wells- During the course of field work, Engineering staff located a monitoring well on the Forest

Service Road 35N02X which accesses Bushy Tail Campground, near its junction with Highway 3 (Map 5).

On 2-3-15, we removed the cap and observed steel casing 2 inches in diameter, and there were 4 rectangular slots in an “+” configuration on the inside of the casing, as is used for accommodating inclinometer probes for measuring inclination of the bore hole. We measured the depth with a tape and weight, and found the well to be 48.8 feet deep, and it had standing water to the top. This segment of the road is built on what looks like a reinforced fill with a wire wall at the base and the well may have been installed to monitor movement on that structure. A road segment about 50 feet wide) has settled about 6 inches in the 5 years or so, and disrupted the asphalt berm on the outside edge of the road. No information was found in the Forest Engineering files regarding this site, but retired Forest

Service personnel advised that it was repaired after a landslide around 1997. Caltrans was contacted

(Scott Lewis, Geologist, Redding office) and they had no information in their files about this well.

Photo 1: Monitoring Well (location on Maps 5 and 6)

Horizontal Drains- Horizontal drains, perforated steel pipe, were identified by Archaeology staff immediately west of the Mule Creek Guard Station below the Forest Service road to the water tank above Bushy Tail Campground (Map 5, Photo 2). Judging from the size of the young conifers growing on the site, the drains are probably on the order of 40 years old, and the landslide does not appear to have moved in the past 10-20 years. A total of 10 pipes were drilled into an excavated embankment at this site, and one of these flowed a trickle of water (1/4? gallon per minute) in early January 2015.

Icicles on the other pipes indicated a small flow from those pipes. These drains may have been installed by Caltrans to drain an unstable area affecting Highway 3. The potential for these drains to provide a conduit for groundwater contamination is very small, since groundwater is actually being discharged here. Furthermore, the drains likely continue to have a stabilizing effect on the recently active landslide. The potential for contamination by animals entering the pipes could be prevented by placing screens on the ends of the pipes (such as those installed on pipes at the Clark Spring development).

Photo 2: Horizontal drains about 2” diameter (see Map 5 for location);

There are also nine horizontal drains observed on the east side of Hwy 3 immediately north of Mule

Creek Guard Station (Photo 3, and Map 5). These are 2 inch diameter steel pipe, and a few dripped a tiny amount of water on 2-3-15.

Photo 3: Horizontal Drains on east side of Highway 3. View SW toward Mule Creek Guard Station

(beyond trees in upper left part of photo)

Leach Lines- Existing leach lines for Bushytail campground are shown on Map 6. Since the area is being considered for siting a vertical well, their location relative to the selected drill site must be carefully evaluated to assure that required offsets are applied, as indicated on Map 6. Similar guidelines would apply to leach lines near the other potential well sites.

Mine Workings- There is an abandoned and collapsed mine adit about ¼ mile southeast of the Mule

Creek Guard station (Photo 2). It is located immediately east of the adit symbol for the “Mule Creek

Mine” on the USGS 7 ½ minute topographic map (Map 5).

A search of the US Geological Survey’s mine data base for the “Mule Creek Mine” revealed that this was a chromite mine worked in the 1940’s during World War 2. However, the locations in the data base are very generalized (referring to sections or quarter sections), and it is shown about a mile north of the area labeled as Mule Creek Mine on the ‘US Geological Survey 7 ½ minute topographic map. As a

Photo 4: Steel rail emerging from collapsed mine adit, notebook for scale (see Map 5 for location);

result, it is uncertain that the mine on the map is the same as the one in the data base. It may be possible to do further research and sort this question out, but since the adit trends away (northward) from any proposed activities, the portal is collapsed shut and buried with soil, and there was no field evidence of fluid discharge, it is very unlikely that it poses a threat to the groundwater system.

GROUNDWATER DEVELOMENT OPTIONS

Horizontal Well-

Site conditions at Clark Spring (Location H3 on Map 4) are very good for intercepting groundwater at a considerable depth below the ground surface with a horizontal well. Figure 1 below is a cross section which shows how far below the ground surface the end of such a well would be if it were drilled 200 feet horizontally into the hillside. The cross section was run with a cloth tape and clinometer, such that errors in horizontal and vertical dimensions on the order of several feet are inherent in this method.

Figure 1: Cross Section at Clark Spring Campground

0 100 200 300 400 500

Clark Spring Cross Section

Figure 2: Cross Section at Clark Spring Campground (without annotation)

Figure 2 is a higher resolution plot without annotation. The approximate location of this cross section is indicated on Map 5. Refraction seismic surveys run in 2004 suggested that hard bedrock lies about 23 feet below the ground surface above Clark Spring (Figure 1), and groundwater may be traveling along the interface between the hard rock and the softer overlying rock of the Weaverville Formation.

Logistically, the road immediately above the spring box (Figure 1) provides the best access for drilling.

This would be about 15 vertical feet above the “potential horizontal well location” shown on Figure 1.

It is recommended that the initial drill hole be directed horizontally into the hill (zero degrees inclination), perpendicular to contour. It is also recommended that the drilling be carefully logged and depth noted when water is encountered. Target length of the hole should be on the order of 200 feet.

If no water is encountered at that length, a second hole should be considered, and its location and orientation should be guided by information gleaned from the first hole. For example, if hard unfractured rock was encountered 80 feet into the first hole, it would make sense to incline the second hole 5 degrees or so uphill to try and intercept the contact between the hard rock and overlying surficial deposits and rock of the Weaverville Formation.

Other Potential Horizontal Drilling Sites Visited on 2-3-15

In addition to Clark Spring proper, three other potential horizontal drilling sites were visited on 2-3-15.

These are shown on Map 4 with thick blue arrows, and labeled H1, H2, H4. GPS locations are indicated on Map 6. These prospects are located in landslide deposits, and the target there would be groundwater within and immediately below those deposits.

Below Mule Creek Guard Station (H1)- This site is at GPS station 403 on Map 6, and would involve drilling from the paved road into a 4 foot road cut, and due to the relatively gentle ground above (35%) would need to be at least 115 feet long in order for the end to be 40 feet below the ground surface.

Clark Spring Parking Lot (H2)- This site is located at GPS station 380 on Map 6, and would involve drilling from the paved parking lot into the cut along the NW margin which is about 30 feet high (Photo 5). This well would need to be about 70 feet long to reach a depth of 40 feet below the ground surface.

Minersville Campground (H4)- This site is located at GPS location 374 on Map 6 (adjacent to the potential vertical drill site).

Photo 5: Parking lot at Clark Spring and possible horizontal well drilling site in the cut near the center of the photo (GPS location 380 on Map 6); Note seepage emerging from asphalt in center of photo;

Ranking of Potential Horizontal Well Drilling Sites

The site at Clark Spring itself is by far the most promising area to drill a horizontal well. The overall ranking of sites in order of decreasing priority is as follows:

1. Clark Spring Campground- Location H3 on Map 4, on the access road immediately above the spring box;

2. Clark Spring Parking Lot- Location H2 on Map 4, in the cut on the NW margin of the parking lot;

3. Below Mule Creek Guard Station- Location H1 on Map 4, in the road cut along the paved access road;

4. Minersville Campground- Location H4 on Map 4, at the base of the steep slope immediately above the loop road;

Potential Vertical Well Sites-

The potential for drilling a vertical well which would produce 5 gallons per minute at a depth of less than

300 feet is good at several locations in the project area. This assessment is based on a review of existing well log data from the peninsula immediately east of the project area, where numerous producing wells are located. These wells were drilled to depths ranging from 90-340 feet, and production rates range from 4 to 75 gallons per minute. Additionally, the Forest Service well at Fawn

Campground (about 1.8 miles to the west) was drilled to a depth of 300 feet, and produced water at a rate of about 15 gallons per minute. It should be noted that there is uncertainty involved in extrapolating data from an adjacent area in this manner, since it is unknown how many dry holes may have been drilled there.

Map 4: Potential Areas for vertical wells (yellow polygons), and horizontal wells (thick blue arrows)

Map 4 identifies 7 potential areas for drilling a vertical well, and the areas are labeled V1-V7. The rock types and geomorphic conditions which would be encountered there would be very similar to those at the existing wells described above (Maps 2 and 3). The potential for tapping groundwater is similar at each of these sites, but they are prioritized below.

Areas V1 and V3- These areas are mapped as ultramafic rock in the Forest bedrock GIS coverage, but there is an outcrop of Copely Greenstone very near Area 1, such that a hole drilled there could possibly encounter some of that rock. These areas are also mantled with landslide deposits. The groundwater target for areas 1 and 3 would be bedrock fractures, though some groundwater could be encountered at the base of the landslide deposits.

Area V2- This area is mapped as Weaverville Formation but adjacent rock outcrop patterns suggest that ultramafic rock underlies the Weaverville Formation at this location. It is also mantled with landslide deposits. The groundwater target here would be permeable zones at the base of the Weaverville

Formation, and bedrock fractures in the ultramafic rock if that unit were encountered. Some groundwater could also be encountered at the base of the landslide deposits.

Areas V4-V7- These areas are also mapped as Weaverville Formation, but underlying rock units could include ultramafic rock, Copeley greenstone, or Bragdon Formation. Landslide deposits mantle areas

V4 and V5. The groundwater target at these areas would be permeable zones at the base of the

Weaverville Formation, and bedrock fractures in the older underlying bedrock if drilling were to encounter these units. In areas 4 and 5, some groundwater could also be encountered at the base of the landslide deposits. Location V6 lacks road access, and has limited flat ground.

Potential Vertical Well Drilling Sites Visited on 2-3-15

Bushytail Campground (Area V4)- Two sites were visited at the campground, GPS locations 372 and 373 on Map 6. Both are on a broad landslide bench, with 373 located higher on the bench.

Minersville Campground (Area V5)- This site is on a broad landslide bench.

Clark Spring Campground (Area V3)- There are several potential drilling sites at this campground, and they have similar potential for encountering groundwater. These include the following GPS locations on

Map 6:

GPS 375- Above the upper loop road, site of an old concrete slab which previously supported a water tank;

GPS 383- Between the two legs of the loop road near camp site #17 (near the center of the campground)

GPS 384-Immediately above the upper loop road in the SW corner of the campground, GPS396- Above the upper loop road, near camp site #2, GPS 397- Above the upper loop road on a broad ridge, near a camp site;

GPS 400- Above the lower loop road near camp site #14;

Ranking of Vertical Drilling Sites-

The best option for drilling a vertical well, would be one of the potential sites identified in the Clark

Spring Campground (GPS locations 375, 383, 384, 396, 397 and 400 on Map 6). Second best would be the lower site at Bushy Tail Campground (GPS 372 on Map 6). Slightly lower priority would be the

Minersville Campground site (GPS 374 on Map 6).

Map 5- Landscape Features-

Map 6: GPS location for sites visited on 2-3-15, including potential well sites;

Map 7: Facilities at Bushytail Campground and required well location offsets at leach fields;

Spring Development at Clark Spring-

Little is known about the construction design of the existing spring box (Photo 3). It may consist of gravel packed around perforated pipe, or possibly a horizontal well drilled into the hillside and cased with perforated pipe. These details should be investigated, and findings used to guide future decisions on development. The current lack of flow into the existing plumbing system could be due to a small drop in water level at the emergence site. Since the spring continues to discharge water into the small stream downslope (Photo 4), it may be possible to remedy the situation deepening the intake pipes.

Photo 6: Spring box at Clark Spring, view uphill; Water in box was 10” deep on 1-2-15

Photo 7: Discharge in stream below Clark Spring on 1-2-15; Culvert is on the road/trail which connects

Clark Spring to Bushy Tail Campground

PREVIOUS GEOLOGIC INVESTIGATIONS

In 1978, Alex Tary, Forest Geotechnical Engineer, conducted a reconnaissance groundwater investigation addressing several campgrounds around Trinity Lake. Sites included Tannery Gulch, Fawn, Hayward Flat, Preacher Meadow, Stony, Cooper Gulch, and Mary Smith campgrounds. Fawn Creek is nearest to the campgrounds being addressed here, and Tary described the well as being 293 feet deep and originally producing about 12 gallons per minute. He interpreted from well logs that the well penetrates about 89 feet of the Weaverville Formation (unconsolidated Tertiary gravels and conglomerate) and then fractured ultramafic rock. He suggests that water is coming from fractures in the ultramafic rock at a depth of about 220 feet. At the time of his visit in 1978, a strong drought was in progress, and the well had ceased producing sufficient water. As a result, he recommended developing an alternative source due to the uncertainty of groundwater levels rising sufficiently for the well to produce again. However, this was not done, and since 1978, the well has produced an adequate amount of water to meet current needs through 2014. The final well construction report (USFS, 1964) describes the drilling of the well which occurred in 1964, and contains a drill log and results of pump tests. Fawn campground is about 1.8 miles SW of Clark Spring.

In 2004, Abel Jasso (Forest Geologist) and Alisha Miller (Assistant Forest Geologist) conducted a field reconnaissance, along with seismic and resistivity surveys at three sites. These were:

1. Clark Spring- Seismic and resistivity surveys were conducted 100 feet upslope from Clark

Spring. It was interpreted that the water from the spring comes from the basal slip surface of a landslide, and this slide plane coincides with the contact between the Weaverville Formation and the underlying peridotite.

2. Clark Spring Boat Ramp- This site is described as being located on: “a terrace immediately south of the boat launch”. This probably refers to Clark Spring boat ramp, and not the

Minersville boat ramp, but in either case, drilling was not recommended at this site, because the terrace deposit was too shallow.

3. Bushy Tail Campground- This site consists of a large landslide bench upon which the campsites for the Bushy Tail campground are located. Seismic surveys indicated high velocity bedrock at a depth of about 20 feet

Jasso and Miller recommended drilling a horizontal well at Clark Spring, but didn’t specify the exact location or depth.

RECOMMENDATIONS ADDRESSING GEOLOGIC HAZARDS AND RESOURCES IN THE PROJECT AREA

The focus of this project is on the groundwater geologic resource, and the primary geologic hazards which exist in the project area include landslides, naturally occurring asbestos, and abandoned mines.

The following actions are recommended to address these resources and hazards.

1. Apply all relevant state and federal standards for drilling and completing the well or wells;

Arrange to have a Forest Service geologist on call during drilling operations to assist in logging the holes and for consultation.

2. Address the potential groundwater contamination sources identified in this report (existing wells and drains, abandoned mines). Potential for contamination can be effectively prevented, but this potential issue should be tracked carefully.

3. Avoid concentrating runoff at drilling sites and prevent runoff from being diverted to unstable areas. This could be accomplished with a field review by Watershed and Engineering personnel to identify the exact locations of the drilling sites.

4. Avoid generation of dust when conducting ground disturbing activities in areas underlain by ultramafic rock (purple polygon on Map 2). This can be accomplished by working when soils are moist, or by applying effective dust abatement measures. This will prevent the introduction of natural asbestos into the air.

5. If the need arises for any activities in the vicinity of the collapsed mine adit located southeast of the Mule Creek Guard Station (Map 5), conduct a more thorough field evaluation and do further literature research into the Mule Creek Mine.

REFERENCES

Jasso, Abel, Miller, Alisha. 2004. Clark Springs Campground Water Well Location Reconnaissance, November 10, 2004. 2 pp plus maps and results of seismic surveys.

Tary, Alex. 1978. Water Supply, Several Campgrounds, Weaverville R.D. 7420 Water Supply, to District

Ranger, Weaverville Ranger District, Attention: Jim Marron, Recreation Officer, January 12, 1978.

USFS 1964. Final Construction Report Drilling of Water Wells at fawn Campground and Trinity Portal

Campground on the Shasta-Trinity National Forest. Contract No. 39-423, 1964, K.W. Kennedy Regional

Engineer, Region 5. Prepared by Clarence Funk, 11-1-64.

USFS, 2014. Shasta-Trinity National Forest Project Initiation Notice. Project Name: Replacement – Clark

Spring Water System; Proponent: Recreation and Fire: Project Leader, Leslie Ross;

USGS. 2014. USGS Mineral Resource Data System (MRDS) geodatabase; contains information on mines, and can be accessed at: http://mrdata.usgs.gov/mineral-resources/mrds-us.html http://mrdata.usgs.gov/mineral-resources/mrds-us.html