WATERSHED and LAKE CHARACTERISTICSBrazilian Elodea

Lake Leland Integrated Aquatic Plant Management Plan


WATERSHED CHARACTERISTICS

Lake Leland (T28N R2W S26) is located in the foothills of the Olympic Mountains in eastern Jefferson County approximately five miles north of Quilcene, WA. It lies within the Hood Canal watershed and more specifically the Little Quilcene subwatershed. The Lake Leland watershed itself contains approximately 3500 acres (Figure 2). Land uses are divided among forestry, agriculture, recreation, and rural residences. The primary land use is forestry, including both public and private timber harvest. Approximately 74 percent of the watershed is in second growth lowland forest. Roughly one percent of the land is used for agriculture and the remaining 25 percent in rural residential areas. The lake shoreline is about 60 percent developed with residences, weekend camp lots, and the Jefferson County Park. This park provides 22 campsites, a boat ramp, swimming area, and fishing dock.

Native vegetation typical of the Pacific northwest is present around the lake. This primarily consists of Douglas fir, western redcedar, western hemlock, red alder, big leaf maple, vine maple, rhododendron, salmonberry, red elderberry, evergreen and red huckleberry, Oregon grape, salal, and swordfern. According to the Natural Heritage Information System, a state sensitive plant species, bristly sedge (Carex comosa), occurs in a wetland at the south end of the lake and along Leland Creek. A rare forested wetland type (western redcedar/western hemlock/skunkcabbage) has also been identified in the northwest quarter of section 23 and is designated Priority 1 for protection by the Natural Heritage Program.

Many unnamed streams and ditches flow into the lake including a major inlet at the north end of the lake. This inlet flows through a wetland before it passes under Highway 101 approximately 300 feet east of the lake. At the west side of the highway, the stream is joined by a drainage ditch which flows from the south and is fed by hillside springs and pasture runoff. This combined flow then proceeds through residential property to the lake. The riparian zone in this area includes willow, maple, spiraea, and various reeds and grasses. The main inlet and several other streams flow throughout the year. There are many subsurface inflows, as any swimmer in the lake can testify. The only surface outflow is Leland Creek located at the south end of the lake. Leland Creek flows into the Little Quilcene River, which flows into the Hood Canal. From the lake, Leland Creek passes through a wetland, past a non-functioning fish weir, and then under Leland Valley Road West. During the winter and into spring, the creek flows over the road at this point. Wetlands surround the north and south ends of the lake and extend along the west side of the lake. There are several isolated wetlands located throughout the watershed (Figure 3), and a snag rich habitat has been identified at the wetland north of the lake (WDFWa 1998).

The topography of the Leland watershed is nearly flat or gently sloping around the immediate lake shore. The topography then steepens to 15-30 percent around most of the lake except in the southwest area where it is 30-50 percent. The highest elevation in the watershed is approximately 880 feet and the lake itself is just under 200 feet in elevation.

The soils in the Leland watershed belong to two different associations: Alderwood-Sinclair and Quilcene-Alderwood-Cathcart . The Alderwood-Sinclair association, the primary soil type, was formed in glacial till under a forest of mixed conifers and broadleaf vegetation. The soils are gravelly throughout and are moderately well drained with moderately rapid permeability. But, a very slowly permeable cemented layer exists at a depth of 20 to 40 inches. During the winter, the perched water table lies above this cemented layer.

On nearly level to rolling slopes, runoff is slow to medium with a slight to moderate chance for water erosion. On the steeper slopes (15-30%), where ravines and steep drainages are found, runoff is medium to rapid, and the danger of water erosion increases from moderate to severe.

The Quilcene-Alderwood-Cathcart association soils formed in shale, sandstone, and glacial till. These soils are located between 200 and 500 feet in elevation on nearly level to very steep slopes. Quilcene soils consist of a surface layer of silt loam and a subsoil of silty clay loam and gravelly clay which is underlain by weathered shale at a 20 to 40 inch depth. The Alderwood soils are a gravelly sandy loam that is underlain by the cemented layer. Cathcart soils have a surface layer of gravelly silt loam and a gravelly loam subsoil that is underlain by sandstone bedrock at 24 to 40 inches depth. This association is moderately well to well drained.

Both of the associations are used for forestry, wildlife habitat, and recreation. A limited amount of clearing has taken place for pasture crops and home gardens. Suitability for septic tanks and drainfields is classified as having severe limitations due to the seasonally perched water tables and slow permeability (USDA 1975).

Land uses in the watershed including forestry, agriculture, and residential development are potential sources of non-point pollution to Lake Leland. Runoff on frozen or saturated soils could result in nutrients and fecal coliform bacteria entering the lake. Logging could increase the sediment load entering the lake. And, because phosphates adhere to soil particles, an increase in sediment load could be accompanied by an increase in phosphorus loading. Logging can also result in higher peak flows and thereby contribute to the flooding problem. Residences and camp trailers along the shoreline and the tributaries of the lake are also potential sources of pollution. Failing septic drainfields could allow both nutrients and bacteria to enter the lake. Lawn and garden fertilizers are another potential nutrient source.

LAKE CHARACTERISTICS

Lake Leland is a shallow lowland lake created by a glacial process. It is about 100 acres in size and has a mean depth of 13 feet and a maximum depth of about 20 feet (Figure 4). The lake, somewhat boot shaped, lies on a north-south axis with three quarters of the lake in a main body and the remaining quarter south of a narrow neck. The lake is about one mile long and has a maximum width of more than 300 feet and a drainage basin of approximately 6 square miles. The 2.8 miles of shoreline gently slope to the lake.

Water Quality

Water quality data for Lake Leland extends back to 1974, although most of the data has been collected since 1993. Water quality monitoring was conducted on the south end of the lake and on the lake’s tributaries for the first time in 1998. Monitoring was intensified during 1998 to obtain the baseline data that is required prior to stocking grass carp, should they be chosen to control Brazilian elodea. Some of the most relevant monitoring data collected by the U.S. Geological Survey, Washington Department of Ecology, and Jefferson County Conservation District are included in this report. A complete, more detailed report will be prepared separately by the Jefferson County Conservation District.

The single most important parameter relevant to Brazilian elodea and other plants is phosphorus. Of the nutrients required, phosphorus is almost always the limiting one in fresh water. Total phosphorus, which includes both available and unavailable forms, appears to have declined in the epilimnion (upper part of the water column) of Lake Leland since 1974, and this decline appears to have continued in recent years (Figures 5 and 6). Chlorophyll a, indicative of phytoplankton abundance, also appears to have declined (Figure 7). This apparent decrease in phytoplankton abundance may explain the slight apparent increase in Secchi disk readings, which indicate an increase in water clarity (Figure 8). Total phosphorus levels were higher in the south end of the lake than in the main lake on each of the four dates sampled (Figure 6).

The apparent decreasing phosphorus and chlorophyll levels and increasing Secchi disk readings could indicate a shift in the plant community from phytoplankton to macrophytes. Certainly, Brazilian elodea is known to have increased in abundance since 1994.

Whether phosphorus is used by phytoplankton or macrophytes, care should be taken to minimize its input into the lake and tributaries. Potential sources of phosphorus are decaying vegetation, animal wastes, fertilizers, detergents, and failing septic drainfields. Minimizing the input of phosphorus from these sources will help minimize the spread of Brazilian elodea. It will also help slow eutrophication, the natural aging process of a lake.

In January 1998, the District monitored 22 of Lake Leland’s tributaries (Figure 9). Many of these were small drains which flowed only during the wet season. We selected the 10 largest tributaries and continued monitoring these through September. Of the 22 tributaries monitored in January, the selected ten accounted for 92% of the phosphorus loading. The highest average phosphorus loadings came from three sources: L/HWY101 and L/WLVR/23 at the north end of the lake, and L/JR/1778 at the south end, where Brazilian elodea is densest.

Of the 22 tributaries monitored in January, the 10 selected tributaries accounted for 97% of the total flow. However, the combined flows from these ten accounted for a much smaller percentage of the lake’s outflow measured in January, February, April, and June (Figure 10). Ground water and surface runoff probably accounted for much of the observed differences during these months and undoubtedly also contributed to the phosphorus loading of the lake. It should be recognized that most of a lake’s annual phosphorus loading can occur during a few major rain events, and our data may not reflect such inputs.

Another important limiting factor which affects the distribution of plants is light. In Lake Leland, plants do not appear to grow at depths much greater than 10 feet. It is noteworthy, however, that Brazilian elodea occurred at the 10 foot (3 meter) depth along 30% of the transects (see Figure 19 in Aquatic Plant Characterization). This is in contrast to fern leaf pondweed (Potamogeton robbinsii), whitestem pondweed (Potamogeton praelongus), and common elodea (Elodea canadensis), which occurred in less than 10% of the transects. Possibly, Brazilian elodea may be more adapted to deep water than native plants. However, to speak of Brazilian elodea as "taking over the lake" is an exaggeration. Planimeter measurements on Figure 4 indicate that only about 30% of the lake is 10 feet deep or less. Thus, under worst case conditions, approximately 70% of the lake would remain free from Brazilian elodea.

Dissolved oxygen is another parameter of interest relative to Brazilian elodea. During the day plants give off oxygen, but at night, when photosynthesis ceases, they actually consume oxygen. In addition, in late summer and fall when plants die back, their decomposition by bacteria and other decomposers also results in oxygen consumption. To better understand how dense stands of Brazilian elodea would affect dissolved oxygen levels, monitoring was conducted in the south end of the lake over a 24-hour period on September 3 and 4. Oxygen was measured every 4 hours at 0.5 meter depth intervals in three habitat types: dense Brazilian elodea, moderately dense Brazilian elodea/whitestem pondweed, and open water with no apparent plants (Figure 11).

Oxygen levels were generally high (8-10 mg/L) in the upper 1-2 meters in all three habitat types; below 1-2 meters, oxygen levels decreased as depth increased. Differences in oxygen levels occurred among the three habitat types, and these differences were generally greatest at the lower depths. However, regardless of depth, the pattern was invariably the same: open water had the highest oxygen levels, the moderately dense stand of Brazilian elodea/whitestem pondweed was next highest, and the dense stand of Brazilian elodea had the lowest levels.

Oxygen levels in lakes normally decrease from surface to bottom and oxygen can be very low near the bottom. Although oxygen levels at these lower depths could not sustain fish for extended periods of time, fish are known to forage in these areas for short durations.

On September 4, some observations were made in the south end of the lake regarding the utilization of dense Brazilian elodea habitat by fish. Juvenile and adult bluegill and juvenile largemouth bass (<3 inches) were frequently observed in small openings or depressions in the otherwise dense stand of elodea. An exception to this appeared to be a 25 foot band near the shore where the Brazilian elodea was coated with filamentous algae. Within this band, there did not appear to be any open water, and no fish were observed.

Water Quantity

As discussed in the Problem Statement, flooding in the Lake Leland area has been a problem for a long time. Dredging and canary grass removal in the upper 2000 feet of Leland Creek in October 1991 lowered the lake level for a while, but it has since returned to its pre-dredging level (Figure 12).

To help assess the flooding problem, the District installed staff gages on Lake Leland and Leland Creek (Figure 13). Gage heights were related to actual elevations for purposes of comparison. A local resident has been monitoring the gages weekly. Data collected so far are shown in Figure 14. The water level at River Mile (RM) 3.5 has been about 2 feet lower than the lake level. Canary grass occupies the channel from about RM 3.7 to RM 4.1 at the lake outlet. Keeping this section of stream free from canary grass could help lower the lake level. However, it is also possible, and even probable, that aquatic macrophytes including Brazilian elodea would replace the canary grass and continue impeding stream flow. The contact herbicide RODEO could be used on the canary grass, but it is ineffective on submersed plants like elodea.

Planting trees along the banks of Leland Creek to shade out aquatic vegetation may be a long term solution to the problem, if the trees could survive the high water table. Besides a tolerance for poor drainage, it would be beneficial for the trees to be evergreen for maximum shading and to be low on a beaver’s preference list. Beaver dams on Leland Creek are another reason for the high lake levels. Beaver dam removal by local volunteers is a continuing process.

 BENEFICIAL USES

Lake Leland offers varied recreational activities for residents and visitors alike. Easy access from state Highway 101 brings many people to Jefferson County Park for camping and picnicking. A public boat launch, fishing dock, and swimming area are maintained by the park (Figure 4). Private docks also provide boaters and swimmers access to the water. The lake supports an excellent warmwater fishery, "the best in the region" according to Washington Department of Fish and Wildlife (WDFW) area biologist Dan Collins. Fishing, boating, swimming and bird watching are only a few of the enjoyable amenities that make Lake Leland one of the most popular lakes in the county. Leland also offers residents and visitors alike a peaceful, rural environment for those who want to relax and just enjoy nature.

The diversity of native vegetation throughout the Leland watershed and the lake supports a wide variety of wildlife. Both eagles and osprey are known to nest in the area and great blue herons and pileated woodpeckers are frequently sighted. Established spotted owl territory exists on the southwest side of the watershed (WDFW 1998a). In winter the migratory trumpeter swan calls the lake home along with Canada geese and an assortment of other waterfowl. Lake Leland has a thriving largemouth bass population. It is reported to contain the highest density of large (> 12 inches) largemouth bass in Western Washington (Collins et al. 1996). Other sought after species include bluegill, black crappie, yellow perch, and rainbow trout.

Besides providing habitat for fish and wildlife and recreation for people, Lake Leland is also a source of domestic water for several residents. To date, there have been eight domestic use water right permits issued for lake waters (Carroll pers. comm. 1998). There are presently three known intakes in use. Potable water is not abundant in the area. A layer of bedrock on the east side of the lake hinders the successful drilling of wells with adequate yields.  


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Contact Kathy Hamel by e-mail at kham461@ecy.wa.gov