Proposition 204 Final Report (Clarks Creek - Summer, 2001) :

Background: The Clarks Creek Project was brought to the FR-CRM by the Plumas National Forest (PNF), Beckwourth Ranger District for inclusion in the Proposition 204 grant proposal and subsequent contract. Clarks Creek drains a 18.7 mi square watershed that receives 35" of annual precipitation predominately as snow. A geomorphic reconstruction of the degradational history indicates that the channel downcutting was likely captured by a cattle trail during historic overgrazing around 1900. This channel capture resulted in rapid downcutting with a concurrent lowering of the shallow meadow water table and subsequent conversion from mesic (moist) site plants to a xeric (dry) site vegetative community. The Clarks Creek watershed is predominately decomposed granite with a high sand sediment supply.

The PNF began restoration efforts on Clarks Creek in 1990 with the development of the Clarks 2000 plan. This plan entailed road closure/rehabilitation, channel stabilization and grazing management changes throughout the watershed. As is the case with many entrenched channel projects, the success of these efforts were short-lived. Without a functional floodplain, channel instability, erosion and habitat loss were experienced in any moderate to major flood. The FR-CRM and the PNF had collaborated on several innovative projects nearby that re-connected the channel to its naturally evolved meadow floodplain (Big Flat, 1995; Bagley Creek, 1997), and considered this concept as a solution at Clarks.

Implementation: Clarks Creek survey and data collection began in the summer of 1999. Groundwater monitoring wells had been installed in 1998 under a grant from the Regional Council of Rural Counties (RCRC) in anticipation of future project work. The final design was completed in early 2000 and the USFS NEPA process begun. The NEPA process was nearing completion in the summer of 2000 when new guidelines for forest management under the Quincy Library Group Forest Plan and the Sierra Nevada Framework were instituted. These changes necessitated additional analyses and delayed project clearance until 2001. Construction began in July 2001 and was completed in early September 2001. The budget for the project was $134,315, including all final design, permitting and construction costs.

The Clarks Creek final design was a collaborative effort between the Forest Service resource specialists, the FR-CRM Technical Advisory Committee (TAC) and the grazing permittee, Doug Robbins. The Clarks Creek meadow system has numerous archaeological sites along the meadow/hillslope margins, sensitive plant occurrences and willow flycatcher habitat in the lower reaches. These resource constraints and grazing management focused the project effort to two of the three meadows targeted for restoration. The permittee was involved and instrumental in developing a grazing management strategy, including exclosure fencing, that would allow for resource use yet protect the project investment.

The contract was advertised by the Plumas County Dept. of Public Works (DPW) and awarded to Kingdon Backhoe of Greenville, Ca. The project entailed obliteration of 3,500 feet of gully, while redirecting streamflow into a well defined remnant channel throughout the meadow. The gully obliteration resulted in the excavation and placement of approximately 23,000 yds3, creating ten small ponds and ten plugs. Several hundred mature willow plants and meadow sod mats were transplanted out of the gully prior to burial or inundation. These transplants were placed in high stress areas of the remnant channel and onto newly-constructed plugs. These plants were sustained during the construction period using a water truck and a 2" pump for irrigation. As a consequence, the transplanting was nearly 100% successful. The project proceeded smoothly with little unforeseen technical difficulty and the project was completed well under budget.

Monitoring/Results:

Clarks Creek was one of the best-monitored projects constructed under this grant. Dave Bogener of DWR conducted pre- and post-project fish and wildlife monitoring. The FR-CRM conducted groundwater level and vegetation monitoring. This report addresses only the groundwater levels and vegetation. The fish and wildlife report is still being prepared by Dave, and should be complete by early 2003.

This report reflects groundwater data collection from 1998 through 2002, and one year of pre-, and one year of post-project vegetation data collection. Construction of the pond-and-plug project was completed in August 2001, hence there is only one growing season and one and a half winters since construction. The first winter after construction was mild (about 70% normal precipitation for water year 2002). The winter before construction was very dry (about 40% normal precip for water year 2001).

Groundwater monitoring:

The wells:

This monitoring regime consists of two control wells and two treatment wells. The control wells were located along the same "cross-section" (unsurveyed), below the road. Well LC1 is located about 60 feet from the gullied channel, and well LC2 about 160 ft. The treatment wells were located on two different surveyed and monumented cross-sections in the uppermost portion of the pond-and-plug treatment. Well UC1 is located on cross-section 2, and well UC 2 is located on cross-section 3. Figure 4 shows the location of the monitoring wells. These wells are located about 50 feet, and 60 feet, respectively, away from the original gullied channel.

Each well is constructed of perforated ½" galvanized pipe, with a cap on the bottom and a cap on the top. The depth of each well varies with the ability to drive the well in with a specially-designed slide-hammer. All wells are driven in using the same protocol- the hammer is placed at the top section of the well, four feet up, and dropped. The number of blows and depth of each well is displayed in Table 1.

Table 1. Clarks Creek well depths and installation.

Well #	Depth (ft)	# blows	Top of pipe to ground (ft)
LC1	11	612	1
LC2	9	400	4
UC1	5	441	2
UC2	14	517	3

Figure 5 displays the results of well monitoring. Wells are monitored by dropping a probe down the pipe, which buzzes when it hits water. The depth of water is recorded. Wells are read about once a month.

Discussion:

Again, it should be noted that there was only about 40% of normal precip for water year 2001, and 70% of normal for water year 2002. Prior to the project, there was a flood in January 1997, and more or less normal water years in 1998, '99, and '00. The graphs in Figure 5 show nearly identical peak water levels at all wells in the spring of 1999 and 2000. However, all those peaks were below the surface elevation of the meadow. Reflecting the poor winter precip in 2001, well peaks were lower in spring 2001.

The project was constructed in summer 2001, and wells were read in fall 2001, following the first storm of the season, hence the peak in wells UC1 and UC2 before 12/25/01, whereas the peak for the control wells did not show until spring 2002. Another noticeable difference between the control and treatment wells after the project is the sustained higher water level in the treatment wells versus the control wells. After project construction, water levels were higher in the treatment wells than at any time previous to treatment, or at any time in the control wells.

Vegetation Monitoring:

At the wells:

Vegetation was monitored pre- and post-project at the two treatment wells. Vegetation was monitored by laying a 75' tape out from the well, 50 feet toward the east (toward the gully), and 25 feet toward the west (away from the gully) at well UC1, and 50' out in each direction (E & W) of the well at UC2. Vegetation was identified to "category" at the boot tip at two-foot intervals. Sage is known to be a dryland species, and the conversion of sage to productive meadow species was an expected project benefit. Table 2 displays the percentage of sage, forb, grass, sedge/rush, willow, bare and litter at each of the two wells before and after the project.

Table 2. Percentage of vegetation categories at each well at Clarks Creek.

Vegetation Category	UC1 before 8/2/01	UC1 after 8/12/02	UC2 before 8/2/01	UC2 after 8/12/02
Willow	0%	5%	0%	0%
Sage	34%	0%	10%	4%
Forb	0%	21%	6%	12%
Grass	34%	37%	24%	46%
Sedge/rush	5%	5%	26%	10%
Litter	16%	10%	24%	12%
Bare	11%	21%	10%	12%

Noticeable changes in vegetation at the wells includes the appearance of willow at UC1, (which may due to the exclosure fence, as much as the higher water table), and the decrease in sage and increase in forbs and grasses at both wells. The decrease in litter at both wells may be due to flowing water carrying littler away, or vegetation covering the litter (at each boot tip, whatever is touched first from the top is what is counted). The increase in "bare" at both wells is definitely due to flowing water. When doing post-project monitoring it was noted that the transects were crossing channels that flowed water earlier in the year. Similarly, the maintenance of percentage of sedges and forbs at UC1, and decrease in this category at UC2 may be due to these species persisting in swales before the project, and getting swept away in flowing water.

On the plugs:
Vegetation cover was cursorily monitored on the plugs in August 2002, which would have given the plugs one growing season. Obviously, there is no pre-project plug veg data, as the plugs did not exist before the project. It should be noted that the plugs were not seeded, but were re-vegetated only with the seed bank in the topsoil that was removed prior to excavation, stockpiled, and then spread out over the plugs. It should also be noted that only the second and third plugs (counting from the upstream end) at each treatment area were monitored, and that the top treatment area is excluded from grazing (except that trespass cows got inside the fence in the spring), and the bottom treatment area was being grazed when the data were collected. Monitoring consisted of one 50" tape randomly placed diagonally on each plug, and the "hit" at boot point at two-foot intervals recorded. In subsequent years all the plugs will be monitored for re-vegetation. Table 3 displays the vegetative cover found on the plugs.

Table 3. Percentage of vegetative cover on monitored plugs at Clarks Creek.

Vegetation Category	Plug 2 (ungrazed) 8/12/02	Plug 3 (ungrazed) 8/12/02	Plug 2 (grazed) 8/13/02	Plug 3 (grazed) 8/13/02
Forb	8%	16%	32%	8%
Litter	20%	24%	12%	24%
Bare	72%	60%	56%	68%

Because the cattle had just started grazing the unit when the data were collected, and there was plenty of feed, they did not cause a noticeable difference between the grazed and un-grazed plugs. By far, all four of the monitored plugs presented here were still mostly bare. Visually, some other plugs appeared more vegetated. It is not expected that the plugs will achieve full re-vegetation until three years after the project.