Land Use Influence on Ecological Function

SWANSON HYDROLOGY + GEOMORPHOLOGY

Chapter 5: Land Use Inﬂ uence On Ecological Function

This chapter summarizes the scientifi c fi ndings and interpretation regarding the ecosystem assessment at Meeks Creek and the infl uence of land use activities on ecosystem function. These analyses and the information developed through this chapter form the basis for proposed restoration approaches and possible management actions described in Chapters 6 and 7.

UPPER WATERSHED AND LOWER MEADOW Meeks Creek above Highway 89 is in good condition with regard to ecological function and the resultant riparian, aquatic and wetland habitats. This relatively high quality function is the result of a naturally high resilience to abrupt geomorphic change; this resilience is the result of geologic characteristics of the underﬁ t stream ﬂ owing over grade controls where coarse cobble/boulder lags have formed in association with recessional moraines and the stabilization effects of dense wetland vegetation. The primary ecosystem function problems in the Lower Meadow above Highway 89 are encroachment of lodgepole pine into meadow areas and possibly some aspects related to the presence of beaver.

A visual inspection of Meeks Creek above Highway 89 reveals diverse and highly functional aquatic and riparian habitats. A comparison survey was made of a typical section of Meeks Creek above Highway 89 with a reach of Blackwood Creek, a stream recently degraded due to cumulative land use effects, and a reach of the Upper Truckee River, a stream highly modiﬁ ed in the early 1900s but now in a state of recovery. A modiﬁ ed version of an assessment technique developed by EPA (2004) was employed to measure physical structure diversity (channel geometry variability) and the diversity in shoreline conditions and presence of large woody debris (LWD) (Figures 5.1 and 5.2a through 5.2e). The results demonstrate that higher quality physical habitat conditions are present in Meeks Creek than are present in Blackwood Creek and Upper Truckee River. Meeks Creek has a low width to depth ratio, provides more complex cover habitat, and contains more large wood. Each of these elements are important in developing the physical conditions that support spawning, rearing, and over-wintering of juvenile and adult salmonids.

SHORELINE ZONE Meeks Creek below Highway 89 is in a highly degraded, ecological state of dysfunction. The channel is deeply incised (4-6 feet) and eroding as a result of dredging for the marina. Incision has reduced the local groundwater table and dried adjacent fl oodplain areas and wetlands. Geomorphic processes are now isolated to a narrow band of the stream bed and little, if any, benefi cial processes are now occurring. The containment of fl ooding and sediment transport has virtually eliminated any benefi cial hydrologic conditions usually present in a lower fl oodplain and shoreline wetland environment.

105 ecological system science hydrology + geomorphology restoration engineering regulatory compliance Blackwood Creek

Lake Tahoe

Meeks Creek (Lower Meadow area above Hwy 89)

Upper Truckee River

SWANSON HYDROLOGY + GEOMORPHOLOGY FIGURE 5.1: Location map of stream survey sites Lake Tahoe, CA. 500 Seabright Ave, Suite 202 Santa Cruz, CA 95062 PH 831.427.0288 FX 831.427.0472 5

Maximum Value

84th Percentile

Mean

2 Stream Depth (ft) Depth Stream 16th Percentile

1 Minimum Value

0 012345678Meeks Creek Blackwood Creek Upper Truckee River (Lower Meadow Area above Hwy 89)

SWANSON HYDROLOGY + GEOMORPHOLOGY FIGURE 5.2a: Diagram showing statistical distribution of stream depth values measured at Meeks Creek (Lower Meadow Area above hwy 500 Seabright Ave, Suite 202 Santa Cruz, CA 95062 89), Blackwood Creek, and Upper Truckee River during 2004 surveys. PH 831.427.0288 FX 831.427.0472 50

Maximum Value 40

84th Percentile 30

Mean

16th 20 Percentile Stream Width (ft) Width Stream

Minimum Value

0 0123456Meeks Creek Blackwood Creek Upper Truckee River (Lower Meadow Area above Hwy 89)

SWANSON HYDROLOGY + GEOMORPHOLOGY FIGURE 5.2b: Diagram showing statistical distribution of stream width values measured at Meeks Creek (Lower Meadow Area 500 Seabright Ave, Suite 202 Santa Cruz, CA 95062 above hwy 89), Blackwood Creek, and Upper Truckee River during 2004 surveys. PH 831.427.0288 FX 831.427.0472 P 814708 FX831.427.0472 PH 831.427.0288 500 Seabright Ave, Suite202 SantaCruz, CA 95062 S WANSON StreamWidth / Depth (ft) 10 20 30 40 50 60 70 80 0

H YDROLOGY 012345678

(Lower Meadow Area above Hwy89) G EOMORPHOLOGY Meeks Creek above hwy 89),Blackwood Creek, and UpperTruckee River during2004 surveys. FIGURE 5.2c:Diagram showing statisticaldistribution ofstream width/depthratiovaluesmeasured atMeeks Creek (Lower MeadowArea Blackwood Creek Mean Minimum Percentile Percentile Maximum Value 16th Value 84th Upper TruckeeRiver Macrophytes Brush / Wood Upper Truckee River Cover Filamentous Algae Blackwood Stream Cover 5% 5% Filamentous Algae Woody Debris 5% Macrophytes 0% 0% Overhanging Vegetation 0% 0% Artificial Structuures Woody Debris 0% 5% Undercut Banks Brush / Wood 0% 5% Boulders 0% Live Trees or Roots 5% Live Trees or Roots 0% Overhanging Vegetation 5% Meeks Creek Stream Cover Undercut Banks 5% (Lower Meadow Area above Boulders Hwy 89) 0% Meeks Stream Cover Filamentous Algae Artificial Structures 0% Open Water 0% 70% Macrophytes 5%

Open Water Upper Truckee River 90% Woody Debris 20% Stream Cover Blackwood Creek Stream Cover Open Water 40%

Brush / Wood 5% Live Trees or Roots 0% Overhanging Vegetation 5%

Artificial Structures 0% Boulders Undercut Banks 5% 20%

SWANSON HYDROLOGY + GEOMORPHOLOGY FIGURE 5.2d: Pie charts illustrating percent of each cover type surveyed at Meeks Creek (Lower Meadow Area above hwy 89), Blackwood 500 Seabright Ave, Suite 202 Santa Cruz, CA 95062 Creek, and Upper Truckee River. PH 831.427.0288 FX 831.427.0472 In Channel Wood Tally

50 45.5

45 LEGEND

MEEKS CREEK (Lower Meadow Area above Hwy 89) 40 BLACKWOOD CREEK

35 UPPER TRUCKEE RIVER

30 27

25 21.9 21

20 16.5

15 Wood Tally per 100 yards of channel 10 10

4.5 5 3 1.8 2 2 2.1 1.2 1 1.51.2 1.5 0.9 000.5 00000.3 0.5 0 0-1 foot 1-2 foot 2-3 foot 0-1 foot 1-2 foot 2-3 foot 0-1 foot 1-2 foot 2-3 foot Log0-15, Diameters 0-1Log 0-15,Diameters 1-2Log Diameters 0-15, 2-3Log Diameters 15-45, 0-1Log Diameters 15-45, 1-2Log Diameters 15-45, 2-3Log Diameters 45-60, 0-1Log Diameters 45-60,Log 1-2 Diameters 45-60, 2-3 0-15 foot Log Lengths 15-45 foot Log Lengths 45-60 foot Log Lengths

SWANSON HYDROLOGY + GEOMORPHOLOGY FIGURE 5.2e: In-channel Wood Talley comparison between Meeks Creek (Lower Meadow Area above hwy 89), Blackwood Creek, and Upper 500 Seabright Ave, Suite 202 Santa Cruz, CA 95062 Truckee River Survey Reaches. PH 831.427.0288 FX 831.427.0472 SWANSON HYDROLOGY + GEOMORPHOLOGY

The ecological function of shoreline wetland systems around Lake Tahoe, such as at the mouth of Meeks Creek, display a range of conditions from highly functional and ecologically valuable (e.g. Trout Creek) to a complete loss of ecological function and wildlife habitat by development (e.g. Burton Creek at Star Harbor on North Shore). The shoreline wetland systems scattered around the perimeter of Lake Tahoe were (and are) the most valuable and diverse areas of wildlife habitat around the lake. These are also the areas of most development pressure and alteration. A census of shoreline wetlands conducted under this study around the lake found over 90% are highly modifi ed and/or hydrologically affected to a point where original ecological function has been severely degraded or the wetland system no longer exists; the lower creek and shoreline area at Meeks is one example of this magnitude of loss. Figure 5.3 shows the results of the census. The census also revealed differences in the size and scale of wetlands supported by different systems. Trout Creek and Taylor/Tallac Creeks are examples of large wetland systems where geological conditions created a broad fl at basin within the shoreline zone. Meeks Creek is more confi ned resulting in a moderate sized wetland similar in scale to General Creek, the next drainage to the north.

Hydrology and geomorphic processes of the shoreline wetlands such as Meeks are highly infl uenced by the water level of Lake Tahoe. Figure 5.4 show the changes at the Upper Truckee River marsh in South Lake Tahoe under various lake stands. Plant growth and sustenance, as well as sediment deposition and the area of open water in the lagoon, are all correlated to high lake stands. The occurrence of high lake stands is also correlated to high streamfl ow, since both occur during wet climatic periods. The fl uctuations in lake level shown in Figure 5.5 occur in response to wet/drought climatic cycles leading to a dynamic process of wetland plant germination, drying, die-off and some survival, followed by invasion of more mesic species. When lake levels rise and the wet conditions are restored, the cycle begins anew. This wetting and drying cycle has occurred at least fi ve times during the 20th century.

The installation of a dam at the Truckee River/Lake Tahoe outlet beginning in 1874 intensiﬁ ed wetland/vegetation processes by raising Lake Tahoe to an average of six feet over maximum natural lake levels (Figure 5.6). A reconstruction of the original hydrology assembled by MBK Engineers (1989) shows an average of two feet higher stage during the spring and summer months; there is similarity in low lake stands with the pre-dam condition. The effect of artiﬁ cially higher stands has been increased shoreline erosion and establishment of higher barrier beach elevations. In addition, the hydraulic response to higher lake stands is to drive the stream base level further inland at shoreline wetlands, and to accelerate sediment deposition higher in the marsh. In contrast, during a drought cycle/lower lake stand episode, the stream would incise through the deltaic deposits and higher elevations of the upper marsh plain would dry out. This phenomenon might explain the recent high rates of sedimentation and invasion of lodgepole pine into the Upper Truckee River Marsh (Rick Robinson, CTC personal. communication 2004).

112 ecological system science hydrology + geomorphology restoration engineering regulatory compliance 0 2.5 5.0 10.0

Miles 1:316,800 N

Stream Disturbance ID Name Rating 18 19 1 Trout Creek Low 1617 2021 2 Upper Truckee River High 15 3 Taylor Creek Low 14 4 Tallac Creek Medium 13 5 Cascade Creek Low 22 6 Eagle Creek Low 23 7 Rubicon Creek High 8 Meeks Creek High 12 9 General Creek Low 11 24 10 McKinney Creek High 25 11 Blackwood Creek High 10 12 Ward Creek High 9 13 Burton Creek High 8 14 Dollar Creek High 15 Watson Creek Medium 7 16 Snow Creek High 26 17 Griff Creek High 27 28 18 First Creek High 5 19 Second Creek High 6 4 1 3 2 20 Third Creek High 21 Incline Creek High 22 Marlette Creek Low 23 Bliss Creek Medium 24 Slaughterhouse Creek High 25 Glenbrook Creek High 26 McFaul Creek High 27 Edgewood Creek High 28 Burke Creek High

LEGEND

# EXTENSIVE EMERGENT MARSH / LAGOON

# WET MEADOW / EPHEMERAL MARSH

# RIPARIAN SCRUB / FOREST

SWANSON HYDROLOGY + GEOMORPHOLOGY FIGURE 5.3: Map of Tahoe basin lagoons. GIS data source: USFS LTBMU. 500 Seabright Ave, Suite 202 Santa Cruz, CA 95062 PH 831.427.0288 FX 831.427.0472 1992 1997 Low Lake Level 6220.4 High Lake Level 6229

0 500 1,000 2,000 0 250 500 1,000

Feet 1:12,000 Feet 1:6,000

SWANSON HYDROLOGY + GEOMORPHOLOGY FIGURE 5.4: Upper Truckee River mouth and marsh changes with different high and low Lake Tahoe levels. Note dry marsh 500 Seabright Ave, Suite 202 Santa Cruz, CA 95062 areas and no lagoon in 1992 during middle of extended drought. During wet year, 1997, note large lagoon, areas of sediment PH 831.427.0288 FX 831.427.0472 deposition (brown and tan areas) and green marsh vegetation. 32 Historical 31 Natural

Elevation (datum = 6200 ft. Lake Tahoe datum) Elevation (datum = 6200 ft. Lake 23

20 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 Water Year

SWANSON HYDROLOGY + GEOMORPHOLOGY FIGURE 5.5: Time series showing the changes in Lake Tahoe levels from 1900 to 1996. Source: MBK Engineers. “Historical” is actual record 500 Seabright Ave, Suite 202 Santa Cruz, CA 95062 taken near outlet in Tahoe City. “Natural” is simulation without effects of dam at Thoe City as prepared by MBK Engineers (1989). PH 831.427.0288 FX 831.427.0472 Lake Tahoe May-August Stage Duration Curves

6232

6231 HistoricalActual NaturalNatural - No Dam - No Dam 6230

6229

6228

6227

6226

6225

6224 Lake Level (Lakefeet) 6,220 Tahoe Datum- 6223

6222

6221

6220

0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1 2 3 4 5 6 7 8 9 100. Percent of Time Water Level is Exceeded

SWANSON HYDROLOGY + GEOMORPHOLOGY FIGURE 5.6: Lake Tahoe Stage Duration Curves during May to August vegetation growing season and peak snowmelt runoff. 500 Seabright Ave, Suite 202 Santa Cruz, CA 95062 “Historical” is with Lake Tahoe Dam regulation, “Natural” is simulation without Dam regulation. Data source: TAHONAT. PH 831.427.0288 FX 831.427.0472 SWANSON HYDROLOGY + GEOMORPHOLOGY

The status of native vegetation, habitat, water quality, macroinvertebrate populations, and ecological function of Meeks Creek below Highway 89 was compared with the same conditions at the mouths of General, Taylor, and Trout Creeks and their functional shoreline wetland systems. These comparisons are useful to understanding the health of the lower ecosystem at Meeks. Transect surveys at each creek location were taken to document topography and the occurrence of vegetation communities. In addition, vegetative/habitat mapping and assessment were completed at the General Creek shoreline wetland, as it is nearby and matches the size and scale of Meeks Creek. Water quality and macro invertebrate sampling also were conducted at Meeks, Taylor, and Trout Creeks. The results of this comparative analysis are summarized below.

VEGETATION A comparison of vegetation transects reveal dramatic differences in ecological function between the highly modifi ed topographic conditions at Meeks Creek versus other natural systems (Figures 5.7A and 5.7B). (See Appendix B for further details of the vegetation study.) It is apparent upon inspection of the General Creek shoreline wetland that the vegetation communities and geomorphic processes are highly infl uenced by the level of Lake Tahoe. General Creek has extensive marsh surface and dense wetland vegetation and riparian habitats occurring between elevations 6,227 and 6,230 feet above sea level (Lake Tahoe Datum). Similar results were found on the other functioning systems. Figure 5.8 shows differences in vegetative species occurrence between Meeks and General Creeks, and Figure 5.9 shows vegetative rooting characteristics. A key fi nding of this assessment is that the topography of Meeks Bay Marina has only a very narrow area of elevation in the critical 6,227 to 6,230 feet range (Figure 5.10). In contrast, the other systems have broad areas of marsh plain within the critical lake level elevations.

SOILS Well-functioning systems such as the shoreline wetland at General Creek have fi ne sediment deposition and periodic inundation well into summer months during wet periods and high lake stands. Subsurface investigation around the Meeks Bay Marina indicate development of peat soils, large deposits of drift and fi ne sediment on marsh surfaces, etc. (Figure 5.11). (See Appendix C for details of subsurface investigation.) Two radiometric C-14 dates of peat soils revealed ages between 1,060 ybp (+/- 50) and 35 years (+/- 20), as well as one dated 3,060 ybp (+/- 150) from pieces of wood deposited in fl oodplain drift. These dates indicate a continuum of peat formation processes up until the marina was dredged in 1960 and fl oodplain deposition processes occurring thousands of years ago.

WATER QUALITY Water quality sampling conducted for this study found that Meeks Creek demonstrated static conditions in terms of water temperature and fl uctuations in dissolved oxygen. This suggests a static system with little diversity (Figure 5.12), as normal biological activity would show ranges in diurnal fl uctuation, such as that of Trout and Taylor Creeks. The static conditions in Meeks Creek, compared to the other sites, are also refl ected in the differences in macro invertebrate

117 ecological system science hydrology + geomorphology restoration engineering regulatory compliance SWANSON HYDROLOGY + GEOMORPHOLOGY FIGURE 5.7a: Cross-sectional comparison of vegetation transects at General and Meeks Creeks prepared by SH+G. General Creek represents 500 Seabright Ave, Suite 202 Santa Cruz, CA 95062 a natural system, with vegetation communities and geomorphic processes infl uenced by the level of Lake Tahoe. Meeks Creek lagoon areas were fi lled/reclaimed and the channel excavated/straightened with development and the construction of Meeks Marina. Without interaction PH 831.427.0288 FX 831.427.0472 between the marsh and fl oodplain surfaces and the level of Lake Tahoe there is a lack of wetland and riparian vegetation in the Shoreline Zone. SWANSON HYDROLOGY + GEOMORPHOLOGY FIGURE 5.7b: Longitudinal profi le comparison of vegetation transects at General and Meeks Creeks. General Creek represents a natural 500 Seabright Ave, Suite 202 Santa Cruz, CA 95062 system, with vegetation communities and geomorphic processes infl uenced by the level of Lake Tahoe. Meeks Creek lagoon areas were fi lled/reclaimed and the channel excavated/straightened with development and the construction of Meeks Marina and now has little PH 831.427.0288 FX 831.427.0472 interaction with the level of Lake Tahoe. Consequently there is a distinct lack of wetland and riparian vegetation in the Shoreline Zone. 100 Meeks Creek Marina Area and General Creek 90 92 80

60 Forbs

50 Graminoides / 46 40

30 Forbs 24 Graminoides /

Number of Species Observed Number of Species 20 14 21 21 16 10 13 7 9 OBL Shrubs FACW Shrubs OBL Trees FACW 0 Trees Meeks General Creek Creek

SWANSON HYDROLOGY + GEOMORPHOLOGY FIGURE 5.8: Histogram of data taken along transect lines by SH+G displaying the number of vascular plant species observed within the 500 Seabright Ave, Suite 202 Santa Cruz, CA 95062 vegetation transect surveys for the mouth of General Creek and Meeks Creek Marina Area. Meeks Creek has a lower species diversity, due PH 831.427.0288 FX 831.427.0472 to the construction of the Meeks Marina and subsequent loss of natural marsh and ﬂ oodplain occurring between the critical elevations of 6227 and 6230 feet above MSL. 2 Juncus spp. Carex spp. 4 pp Populus 6 balsamifera ssp. trichocarpa 8 Pinus contorta 10 ssp. murrayana

Depth from Surface (ft) Depth from Surface Pinus jeffreyi

Generalized Root-Depth / Soil Moisture Requirements for Selected Herbaceous, Shrub and Tree Species

SWANSON HYDROLOGY + GEOMORPHOLOGY FIGURE 5.9: Generalized rooting depth and soil moisture requirements for select herbaceous, shrub and tree species found in and near 500 Seabright Ave, Suite 202 Santa Cruz, CA 95062 shoreline and wetted areas in the Lake Tahoe Basin. Given the highly disturbed nature of Meeks Creek in the Shoreline Zone, many of these PH 831.427.0288 FX 831.427.0472 species are unable to grow at the site. MEEKS CREEK

GENERAL CREEK 6228’

SWANSON HYDROLOGY + GEOMORPHOLOGY FIGURE 5.10: Photo comparison of habitat quality in Meeks and General Creek Shoreline Zones. The elevation of 6228’ is critical for the persistance of important riparian and 500 Seabright Ave, Suite 202 Santa Cruz, CA 95062 wetland vegetation species. Notice that General Creek has a much broader range of PH 831.427.0288 FX 831.427.0472 topography occurring at this elevation, while Meeks Creek is dominated by the Marina. Cross Section NW-4 6240 Cross Section S-2 At 67” depth 6240 6238 6238 At 53” depth Wood Piece Peat 6236 3,060 ybp 6236 35 ybp TP_6 TP_105 TP_5 6234 6234 6233.7 6233.3 TP_7 6233.5 TP_11 6232.5 TP_8 TP_104 6231.9 6232 6232.3 TP_9 TP_8 6232 6232 6232 6231.9 TP_3 6230 6229.1 6230 Elevation 6228 Elevation

6228 6226

6224 6226

6222 6224

6220 0 50 100 150 200 250 300 350 400 450 500 550 6 6222 Distance

6220 150’ south 0 50 100 150 200 250 300 350 400 450 500 550 Distance in Pit #1

Project: Meeks Creek Legend Plan View At 72” depth Peat Project: Meeks Creek Watershed Assessment Legend Plan View 1090 ybp Cross Section Location Map Cross Section N-2 6240

6238 101 6236 102 !(

!( 6234 103 TP_104 !( !( N-2 6232.3 6232 105 !( TP_101 TP_102 TP_103 3 6230.1 6230.2 6230.1 !( 6230 104 Elevation 6 6228 NW-4 !( S-2 2 !( 7 6226 !( !( 7a !( !( 10 9 !( 1 !( 8 6224 !( 7b !( 4 11 6222 !(

6220 5 0 50 100 150 200 250 300 350 400 450 Distance

Project: Meeks Creek Assessment Legend Plan View

SWANSON HYDROLOGY + GEOMORPHOLOGY FIGURE 5.11: Results of soil trenching geology survey of Meeks Marina. Soil core samples were collected in August of 2004. 500 Seabright Ave, Suite 202 Santa Cruz, CA 95062 Selected C-14 sample dates are noted. PH 831.427.0288 FX 831.427.0472 12

6 Degree C Degree

2 Diurnal Variation in temperature (Degrees C) in temperature Variation Diurnal 0 Meeks Taylor Tallac Baldwin

100

50 Percent

10 Diurnal Variation in Disolved Oxygen (Percent) Variation Diurnal 0 Meeks Taylor Tallac Baldwin

Percent Saturation 10

5 Percent Dissolved Oxygen Saturation (Daytime) Dissolved Oxygen Saturation Percent 0 Meeks Taylor Tallac Baldwin Trout

SWANSON HYDROLOGY + GEOMORPHOLOGY FIGURE 5.12: Water quality graphs, showing the effects of the Marina excavation on the 500 Seabright Ave, Suite 202 Santa Cruz, CA 95062 water temperature and dissolved oxygen within the Shoreline Zone of Meeks Creek, compared to more natural systems. PH 831.427.0288 FX 831.427.0472 SWANSON HYDROLOGY + GEOMORPHOLOGY

populations, with Meeks showing an afﬁ nity towards species more adapted to degraded conditions (Figure 5.13). Sampling for anthropogenic pollution in Meeks revealed the presence of selected metals and some hydrocarbons, which are likely related to the marina and boat operations (Figure 5.14). Although the concentrations of these pollutants were not high, their presence indicate a degree of contamination from marina operations not found at the other sites, and it is possible that higher contaminant levels may be present in other portions of the marina area not sampled. (See Appendix C for details of geotechnical and pollutant survey of Meeks Marina.)

SH+G conducted water quality monitoring of Meeks Creek during the 2004 water year to collect data on the inﬂ owing waters of Meeks Creek, to investigate the inﬂ uence of the marina operations on the lagoon system, and to compare the Meeks system to water quality of other Lake Tahoe watersheds.

A multi-parameter probe was installed and maintained at the Highway 89 bridge from October 2003 through September 2004. On 30-minute intervals the probe collected ancillary water quality data, including water depth, temperature, and turbidity (Figure 5.15). The annual hydrograph illustrates the typical low fl ow summer and fall conditions with runoff from a few winter rain storms, followed by the seasonal snowmelt. Water temperatures in the winter are consistently at or below freezing. As the seasons change, the extreme daily variation in stream temperature is apparent, and indicates a consistent warming trend through late summer. While the highest turbidity values were observed (149 NTU) during the peak of the spring snowmelt, a greater amount of particulates appear to have been transported through the system during early winter rainstorms in mid-October and November 2003, and the summer thunderstorms in August 2004, than the entire spring melt. The same conditions have been observed in stream monitoring from the Upper Truckee River by the City of South Lake Tahoe. This difference refl ects severable variables, including the greater and widespread contributing areas of sediment sources during rainstorms versus the limited areas of spring snowmelt runoff, and increased infi ltration to shallow groundwater eventually recharging streamfl ow at lower elevations.

Total organic carbon (TOC) and dissolved organic carbon (DOC) levels were measured in surface water samples collected from four Lake Tahoe Basin lagoons (i.e., Meeks, Trout, Tallac, and Taylor Creek locations) and their respective infl owing waters. Each lagoon and infl ow sample was collected between 8 and 10 am over a 3-day period (August 29 through August 31, 2004). All comparative lagoons (Taylor, Tallac, and Trout Creek) appear to sequester organic carbon relative to the infl owing waters (Figure 5.16), which is typical of naturally functioning lagoon system. A natural function converts inorganic nutrients to organic matter (i.e. biomass). Samples collected from the Meeks Creek Watershed indicate a disruption of this natural function in contrast to the Trout, Tallac, and Taylor Creek locations. It must be noted that the Meeks Creek infl owing TOC and DOC values are the highest observed, most likely due to the backwater conditions caused by persistent beaver activity in the Highway 89 culvert. Regardless, one would expect an additional increase in TOC and DOC levels once waters enter and are cycled through the lagoon system in August.

125 ecological system science hydrology + geomorphology restoration engineering regulatory compliance 25

Number of Species of Number 10

0 Trout Creek lagoon Baldwin Beach lagoon Taylor Creek lagoon Meeks vegetated margins Meeks Marina

Emergent Vegetation: Emergent Vegetation: Emergent Vegetation: present absent absent Depth: 5 - 25 cm Depth: 25 - 100 cm Depth: 150-200 cm

SWANSON HYDROLOGY + GEOMORPHOLOGY FIGURE 5.13: Differences in invertebrate diversity in several lagoon habitats of Lake Tahoe Basin. 500 Seabright Ave, Suite 202 Santa Cruz, CA 95062 PH 831.427.0288 FX 831.427.0472 Pb Conc (mg/kg) Cu Conc (mg/kg) 0 5 10 15 20 25 01234567 0 0

1 1

2 2

3 3 Depth in sediments (ft) Depth in sediments (ft)

4 4

5 5 Pb DL 1 mg/kg Cu DL 1 mg/kg Site A Site B 6 Site C 6 Site D Site E

SWANSON HYDROLOGY + GEOMORPHOLOGY FIGURE 5.14: Spatial distribution of trace metals in sediments sampled in Meeks Marina. Samples collected October 7, 2003. See 500 Seabright Ave, Suite 202 Santa Cruz, CA 95062 Figure 5.17 for locations of sediment sampling sites. PH 831.427.0288 FX 831.427.0472 Meeks Creek Monitoring 2004 (Hwy 89)

100

mean daily discharge (cfs) 0 Oct-03 Nov-03 Dec-03 Jan-04 Feb-04 Mar-04 Apr-04 May-04 Jun-04 Jul-04 Aug-04 Sep-04 40 30 20 No Data 10 Available 0 water temp (deg C) -10 Oct-03 Nov-03 Dec-03 Jan-04 Feb-04 Mar-04 Apr-04 May-04 Jun-04 Jul-04 Aug-04 Sep-04

160 140 120 Spring Snowmelt 100 Winter Rain 80 Summer Thunderstorms 60 turbidity (NTU) 40 20 0 Oct-03 Nov-03 Dec-03 Jan-04 Feb-04 Mar-04 Apr-04 May-04 Jun-04 Jul-04 Aug-04 Sep-04

SWANSON HYDROLOGY + GEOMORPHOLOGY FIGURE 5.15: Water quality monitoring of Meeks Creek inﬂ ow at Highway 89. Data collected by SH+G with a YSI 600OMS installed at the 500 Seabright Ave, Suite 202 Santa Cruz, CA 95062 upstream end of the Highway 89 culvert and recording data on 30-minute intervals. PH 831.427.0288 FX 831.427.0472 Tahoe Lagoon Organic Carbon Comparisons Sampled August 29-Aug 31, 2004 7 TOC Meeks Inflow (Hwy 6 89) Taylor Creek Lagoon Tallac Creek Lagoon 5 Trout Lagoon

3 Tallac Creek Inflow Meeks Lagoon (B) 2 Trout Creek Inflow Total Organic Carbon (mg/L) Taylor Inflow 1

6 DOC Meeks Inflow (Hwy 5 89)

4 Tallac Creek Lagoon Trout Lagoon 3 Meeks Lagoon (B) Tallac Creek Inflow 2 Taylor Creek Lagoon Trout Creek Inflow Dissolved Organic Carbon (mg/L) 1 Taylor Inflow

SWANSON HYDROLOGY + GEOMORPHOLOGY FIGURE 5.16: Results of TOC and DOC sampling at the inﬂ ow and lagoons of Meeks, Trout, Taylor, and Tallac Creeks. Trout, Taylor, and Tallac systems act as expected, with 500 Seabright Ave, Suite 202 Santa Cruz, CA 95062 TOC and DOC concentrations increasing with biological activity in the lagoon. Results at PH 831.427.0288 FX 831.427.0472 Meeks illustrate the lack of biolgical activity in the degraded marina system. SWANSON HYDROLOGY + GEOMORPHOLOGY

Nutrient grab samples were collected monthly from four locations in the Meeks Creek Watershed (see Figure 5.17) from September 2002 through September 2004. The sampling locations were at the Highway 89 Bridge (inﬂ ow), at the inlet to the Marina (Site A), in the middle of the Marina (Site B), and 100 feet upstream of the shoreline at Lake Tahoe where the marina outﬂ ow is constricted through the sheet piling dividing the barrier beach (Site C) (Figure 5.17).

Comparison of biologically available nitrogen and phosphorous species observed at Meeks Creek inﬂ ow (Figure 5.18, SH+G data for 2003-2004) to General and Trout Creeks (Figure 5.18, USGS data for 2002-2003) illustrate that all sites over the course of the year are relatively similar. Soluble reactive phosphorus (SRP) and dissolved phosphorous (DP) values appear to be slightly higher in the western basins north of Meeks Creek (Blackwood and Ward Creeks) likely due to the predominance of phosphorous-rich volcanic deposits in these areas. Nitrate and ammonia species in Meeks Creek are similar to those observed in General Creek, typical of what is expected for an undeveloped Lake Tahoe watershed.

As water moves through the marina (Site A to Site C on Figure 5.17), there is very little change observed in the biologically available nutrient levels (Figures 5.19). We would expect to see declines in nitrate, ammonia, and SRP in surface water within the lagoon relative to the contributing waters during the warm summer months of May through September. The decline would result from biological uptake and biogeochemical cycling in a ‘productive and functional’ lagoon. The stable nutrient concentration observed from the inﬂ ow to the marina support the decline in TOC and DOC levels (Figure 5.16) as water moves into the marina. If the marina were a functional and productive lagoon system, changes in nutrient levels over time would be expected; however, no seasonal component of biogeochemical cycling is apparent at Meeks Bay Marina. The nutrient time series and organic carbon data provide further evidence that Meeks Bay Marina is not functioning as a natural system at the base of the food chain. These factors would be expected to magnify moving upward though the trophic order.

FISHERIES Meeks Creek supports a range of native and non-native fi sh species that are segregated based on location in the watershed (Figure 5.20). In the lagoon reach below Highway 89, a total of ten species are present including salmonids, whitefi sh, minnow species, suckers, and sculpin (Table 5.1); see Appendix A for detailed fi sh study. Despite deleterious land use infl uences on the lower reach, a moderate level of diversity of habitat types might be expected as a result of fl uctuating lake level, low velocity areas, and the potential of high primary productivity typical of lagoons. Upstream of Highway 89 the low gradient meadow reach provides the high quality habitat within the lower watershed with six species still present. These include the salmonids, tahoe sucker, and speckled dace. The Highway 89 crossing may be a barrier to kokanee which are present in the lagoon reach (Figures 5.21A and B). At approximately the wilderness boundary a series of waterfalls and cascades impedes upstream movement of fi sh. Consequently, the only species

130 ecological system science hydrology + geomorphology restoration engineering regulatory compliance LEGEND

WATER QUALITY and SEDIMENT SAMPLING SITES

SEDIMENT SAMPLING SITES

D C

B A

0 50 100 200

Feet 1:1200

SWANSON HYDROLOGY + GEOMORPHOLOGY FIGURE 5.17: Map indicating locations of nutrient grab sampling and sediment core samples in Meeks Marina. 500 Seabright Ave, Suite 202 Santa Cruz, CA 95062 PH 831.427.0288 FX 831.427.0472 Inflow Nutrient Data 2003-2004 USGS Data (General #10336645 and Trout #10336775) and SHG Data (Meeks)

20 Meeks 15 General 10 Trout Nitrate (ug/L) Nitrate 5

25 20 Meeks 15 General 10 Trout

Ammonia (ug/L) Ammonia 5 0

30 Meeks

20 General (ug/L) Trout 10

0 Soluble Reactive Phosphorous Phosphorous Reactive Soluble

60 50 40 Meeks 30 General 20 Trout 10

Dissolved Phosphorous (ug/L) Phosphorous Dissolved 0

200

150

100 Meeks General 50

Mean Daily Discharge (cfs) 0 Jul-03 Jul-04 Jan-03 Jan-04 Sep-02 Sep-03 Sep-04 Nov-02 Mar-03 Nov-03 Mar-04 May-03 May-04

SWANSON HYDROLOGY + GEOMORPHOLOGY FIGURE 5.18: Comparison of results of nutrient grab samples collected from Meeks 500 Seabright Ave, Suite 202 Santa Cruz, CA 95062 Creek inﬂ ow at Highway 89 during WY2003-04 and General and Trout Creeks from PH 831.427.0288 FX 831.427.0472 USGS data in WY2003. Meeks Creek Watershed Assessment Marina sampling 2003-2004 Inflow and Sites A, B, and C 16

12 Inflow 8 Site A Site B Site C Nitrate (ug/L) 4

25 20 15 Inflow Site A 10 Site B Site C

Ammonia (ug/L) 5 0

350 300 250 200 Inflow Site A 150

TKN (ug/L) Site B 100 Site C 50 0

20 SRP Inflow DP Inflow 15 SRP A DP A 10 SRP B DP B 5 SRP C

Phosphorous Species (ug/L) DP C 0 25 20 Inflow 15 Site A Site B 10 Site C 5 0 Particulate Phosphorous (ug/L) Jul-04 Jul-03 Jan-04 Jun-04 Oct-04 Oct-03 Feb-04 Sep-04 Sep-03 Apr-04 Dec-03 Nov-03 Aug-04 Aug-03 Mar-04 May-04

SWANSON HYDROLOGY + GEOMORPHOLOGY FIGURE 5.19: Comparison of results of nutrient grab samples collected at inﬂ ow at 500 Seabright Ave, Suite 202 Santa Cruz, CA 95062 Highway 89 and at Sites A, B and C in Meeks Creek Marina. See Figure 5.17 for location PH 831.427.0288 FX 831.427.0472 of water quality site. SRP- Soluble Reactive Phosphorous; DP- Dissolved Phosphorous. 0 3/8 3/4 1.5 Miles 1:47,520 LEGEND N HIGHWAYS STREETS / ROADS LAKE / POND MEEKS CREEK MAINSTEM REACH BREAKS 89 FISH SPECIES BROOK TROUT BROWN TROUT MOUNTAIN WHITEFISH RAINBOW TROUT SPECKLED DACE TAHOE SUCKER KOKANEELAKE TUI CHUB TAHOE LAHONTAN REDSIDE PAIUT SCULPIN

LAKE TAHOE

89 EMERALD BAY

SWANSON HYDROLOGY + GEOMORPHOLOGY FIGURE 5.20: Map of ﬁ sh species occurence in Meeks Creek. 500 Seabright Ave, Suite 202 Santa Cruz, CA 95062 GIS data source: USFS LTBMU PH 831.427.0288 FX 831.427.0472 General Trout Capabilities*: sustained swimming speed = 4.0 ft/sec minimum depth of water = 0.5 ft maximum jump height = 2.0 ft

V = unfavorable conditions for ﬁ sh passage

D * Fish passage criteria taken from Bell 1991, and Flosi 1997.

H Velocity in Culvert Outlet (ft/s) Lake Stand Elevation (ft) Q (cfs) 6228 6227 6226 6225 2 1.42 1.42 1.42 1.42 10 2.39 2.39 2.39 2.39 55 4.19 4.19 4.19 4.19

Depth of water in Culvert Outlet (ft) Lake Stand Elevation (ft) Q (cfs) 6228 6227 6226 6225 2 0.06 0.06 0.06 0.06 10 0.17 0.17 0.17 0.17 55 0.55 0.55 0.55 0.55

Jump Height at Culvert Outlet (ft) Lake Stand Elevation (ft) Q (cfs) 6228 6227 6226 6225 2 1.4 2.4 2.85 2.86 10 1.4 2.37 2.63 2.68 55 1.33 1.99 2.05 2.05

Note: Lake Stand Elevations based on NGVD 29.

SWANSON HYDROLOGY + GEOMORPHOLOGY FIGURE 5.21a: The Highway 89 bridge may be a barrier to ﬁ sh migration. 500 Seabright Ave, Suite 202 Santa Cruz, CA 95062 PH 831.427.0288 FX 831.427.0472 Meeks Creek Plan: FishRuns Meeks Creek Plan: FishRuns RS = 1530 Culv Meeks Lower 6240 .035 .05 HEC RAS model profile of culvert HEC RAS model cross section of downstream end of culvert

6238

6240

6236 46.5'

6234

6235 12'

6232

Elevation (ft) S = 0.0011 Elevation (ft) 7.6'

55 cfs 6230 10 cfs 2 cfs

6230 55 cfs 10 cfs 2 cfs 6228

6226 Model analyzes hydraulic effects at various lake stand elevations for low, moderate, and high mean daily flows.

6225 800 810 820 830 840 850 860 1440 1460 1480 1500 1520

Station (ft) Main Channel Distance (ft)

Velocity (V) in Culvert Outlet (ft/s) Lake Stand Elevation (ft) Q (cfs) 6228 6227 6226 6225 2 1.42 1.42 1.42 1.42 10 2.39 2.39 2.39 2.39 55 4.19 4.19 4.19 4.19

Depth of water (D) in Culvert Outlet (ft) V Lake Stand Elevation (ft) Q (cfs) 6228 6227 6226 6225 D 2 0.06 0.06 0.06 0.06 10 0.17 0.17 0.17 0.17 55 0.55 0.55 0.55 0.55 H Jump Height (H) at Culvert Outlet (ft) Lake Stand Elevation (ft) Q (cfs) 6228 6227 6226 6225 2 1.4 2.4 2.85 2.86 10 1.4 2.37 2.63 2.68 55 1.33 1.99 2.05 2.05

Note: Lake Stand Elevations based on NGVD 29.

SWANSON HYDROLOGY + GEOMORPHOLOGY FIGURE 5.21b: Highway 89 bridge may be a barrier to ﬁ sh migration. 500 Seabright Ave, Suite 202 Santa Cruz, CA 95062 PH 831.427.0288 FX 831.427.0472 SWANSON HYDROLOGY + GEOMORPHOLOGY

present in the upstream reach are the introduced salmonid species and mountain whiteﬁ sh; ﬁ sh are not likely native to the upper watershed. Habitat conditions consisting of a high-gradient channel dominated by a step-pool morphology favors these drift feeders. Farther up in the watershed as physical conditions become harsher the only remaining species is the hardy brook trout.

Table 5.1: Presence and Distribution of Fish Species with the Meeks Creek Watershed (see Appendix A) Common Name Scientiﬁ c Name Distribution Lahontan redside Richardsonius egregious Lagoon Reach Paiute sculpin Cottus beldingii Lagoon Reach Tui chub Gila bicolor Lagoon Reach rainbow trout Oncorhynchus mykiss Lagoon Reach, Lower Watershed brown trout Salmo trutta Watershed-wide kokanee salmon Oncorhynchus nerka Lagoon Reach brook trout Salvelinus fontinalis Watershed-wide Tahoe sucker Catostomus tahoensis Lagoon and Meadow Reaches Mountain whiteﬁ sh Prosopium williamsoni Lagoon Reach, Lower Watershed Speckled dace Rhinichthys osculus Lagoon and Meadow Reaches

HABITAT CONDITIONS An analysis of vegetative and wildlife habitat conditions in General and Meeks Creeks was conducted using metrics of several wildlife value indices (Figure 5.22); see Appendix B for vegetation survey and Appendix D for wildlife resources survey of Meeks Creek Watershed. It is apparent that General Creek has a patchy habitat structure resulting from cycles of high and low lake stands interacting with ﬂ oods, favoring many bird and mammal species. For example, the length of willow scrub edge to meadow and to conifer forest in relation to overall meadow area reﬂ ects value for avian and terrestrial species.] A simple comparison of individual willow scrub sizes and number between Meeks and General Creeks demonstrates a notable difference in habitat quality, despite the fact that the potential riparian/meadow area of Meeks is greater than General Creek. A mapping of estimated vegetation at Meeks Creek in 1939, prior to the marina construction, shows similar characteristics and value to present-day General Creek (see Figures 5.23 and 5.24), and is evidence of historic degradation.

In summary, the historic land use activities at Meeks Creek have changed the natural ecosystem and the physical and biotic processes supporting ecosystem function:

1) Clear cutting in the mid to late 1800s removed all of the virgin old growth timber stands in the lower watershed. All trees over 15 inches in diameter were removed. Fire suppression since the early 1900s, along with clear cuts in the 1800s, led to the present forest structure that is dominated by dense single aged stands of white ﬁ r. Conifer species have shifted from a dominance of Jeffrey pine to dense white ﬁ r and lodgepole pine. 137 ecological system science hydrology + geomorphology restoration engineering regulatory compliance 80000 0.3

Meeks Creek Meeks Creek General Creek 70000 General Creek

60000

0.2 50000

40000 Area (sq ft) (sq Area

30000 0.1 Proportion of Total Lake Influence Zone 20000

10000

0 0 Willow>2m Alder>2m Total Riparian Shrub Meadow Willow>2m Alder>2m Total Riparian Shrub Meadow

100

Meeks Creek 1400 90 General Creek

80 1200

70 1000

800 50 Number Per Acre 40 SizePatch (sq ft) 600

30 400

200 10

0 0 Standing Snags Downed Logs Meeks Creek General Creek Habitat Element

SWANSON HYDROLOGY + GEOMORPHOLOGY FIGURE 5.22: Comparison of vegetation metrics for wildlife habitat indices for Meeks and General Creeks. Data mapped by River 500 Seabright Ave, Suite 202 Santa Cruz, CA 95062 Run and Wildlife Resources Consulting. PH 831.427.0288 FX 831.427.0472 LEGEND

1939 ESTIMATED CHANNEL ALIGNMENT

VEGETATION / LAND COVER

OPEN WATER

WILLOW / WETLAND RIPARIAN N CONIFER FOREST

BARE GROUND

FILL 0 150 300 600

Feet 1:3,600

SWANSON HYDROLOGY + GEOMORPHOLOGY FIGURE 5.23: Estimated pre-marina vegetation conditions at shoreline zone of Meeks Creek Watershed displayed over 1939 aerial photo. 500 Seabright Ave, Suite 202 Santa Cruz, CA 95062 Aerial photo source: USFS LTBMU. PH 831.427.0288 FX 831.427.0472 2003

1950s

SWANSON HYDROLOGY + GEOMORPHOLOGY FIGURE 5.24: Aerial comparison of the mouth of Meeks Creek, pre-and post-Marina construction. Note extensive lagoon and will scrub/ 500 Seabright Ave, Suite 202 Santa Cruz, CA 95062 meadow vegetation in 1950 which is completely absent in 2003. Also note dense conifer forest cover on meadow upstream of highway 89 in 1950’s versus post-harvesting conditions in 2003. PH 831.427.0288 FX 831.427.0472 SWANSON HYDROLOGY + GEOMORPHOLOGY

2) Washoe traditional stewardship practices at Meeks Creek Watershed included controlled burning of meadows and forest understory, and harvesting and cultivation of a variety of native plants for medicinal and food needs. These practices were curtailed and then eliminated in the early 1900s. This likely led to the invasion of dense stands of lodgepole pines into meadow areas, visible in 1939 aerials. The LTBMU conducted mechanical thinning to reduce dense lodgepole stands in the early 1990s; the LTBMU also issued a special use permit for the Washoe to collect native plants in the lower meadow.

3) The original shoreline wetland at Meeks Bay has been highly altered as a result of development of the Meeks Bay Resort and Marina, and Meeks Bay Campground. Historical aerial photographs show elements of a functional lagoon and marsh system, which supported native vegetation communities and fi sh habitat. The shoreline wetland/ lagoon system was lost when the Meeks Bay Marina was constructed in 1960, along with associated dredging and fi lling of the lower fl oodplain areas. This created a confi guration that eliminated landforms at the proper elevations to support wetland vegetation. Furthermore, the present marina has created a static physical system, eliminating the dynamic geomorphic processes necessary to sustain a functional ecosystem.

4) The dredging of the marina and the construction of the Highway 89 bridge has caused severe channel bed incision in Meeks Creek between the Lake Tahoe shoreline and Highway 89. The incision has caused severe and chronic bank erosion and drying of the ﬂ oodplain surface, which once supported wetland and riparian vegetation and habitat.

141 ecological system science hydrology + geomorphology restoration engineering regulatory compliance