- Clatsop County)
(From Atlas of Oregon Lakes, Johnson et al. 1985). Cullaby Lake is the largest of the many lakes on the Clatsop Plains of the north Oregon coast. It was originally known as Ya-se-ya-ma-na-la-tslas-tie, but was later named for Cullaby, a well-known Indian character of the region. Cullaby had a peculiar light complexion and was reputed to be a grandson of one of the members of the Lewis and Clark Expedition that wintered nearby in 1804-05. The geologic origin of Cullaby Lake is similar to that of many others on the Oregon coast. The mouth of a coastal stream was drowned by the post-Pleistocene rise in sea level and, subsequently, separated from the ocean by migrating sand dunes. This type of formation produces a lake with a characteristic dendritic (branching) shape, in contrast with the long and narrow interdune lakes of the Clatsop Plains such as Coffenbury, Smith and Sunset. However, Cullaby Lake is not nearly as dendritic as many other coastal lakes, Tahkenitch and Siltcoos, for example. The margin of the upland behind the Clatsop Plains describes a gentle, regular curve which marks a coastal bluff developed during an earlier period of high sea level. The site of Cullaby Lake is a broad indentation in this bluff. Thus, it now lies in a shallow depression bordered on the west by relict sand dunes and on the east by low hills of the Coast Range.
The two-mile long lake is fed by several small streams; the largest is Cullaby Creek, draining an extensive swampy area at the south end which includes cranberry bogs. Outflow is north through a ditch into Skipanon Creek, entering the Columbia River about six miles to the north. Originally the lake drained through Neacoxie Creek which flowed northward before turning south into the Necanicum River estuary, but shifting sand dunes and road construction interfered with the flow of the creek and altered the drainage to its present coarse. Water level in the lake now fluctuates from a low of about 7.5 feet above mean sea level in the fall to about 9.5 feet in the early spring. The level can, within limits, be regulated by a weir across the entrance to the ditch.
As noted, a fairly extensive cranberry culture has developed on the south shore of the lake. Otherwise, the surrounding landscape is mostly covered by a spruce-hemlock forest. Private timber companies own most of the land on forested slopes to the east. As seen in the accompanying air photo, much of this land has been logged off in the last few years and regrowth has barely begun. The north and west shoreline of the lake is zoned residential and there are several private homes at the north end which are connected to sewer lines.
The main focus of recreational activity at Cullaby Lake is the warm-water fishery. Pan fishing is excellent from spring through late fall; crappies, bluegill, perch, catfish, and largemouth bass are all taken. In fact, a Portland bass-fishing club holds an annual tournament here. Fishing for catfish is said to be particularly good at the south end of the lake. Cutthroat and rainbow trout are also found in the lake, but generally not fished with much success. Clatsop County maintains a large park, Cullaby Lake Park, on the northwest shore; it includes a boat ramp and dock, restrooms, playground, picnic tables and a sandy beach. There are no overnight facilities at the lake.
From a water quality standpoint, the distinguishing characteristic of Cullaby Lake is its high concentration of dissolved organic matter (McHugh 1972). Lake water is deeply stained with a dark brown color and the transparency is consequently reduced. Large marshy areas around the shoreline, particularly at the south end, contribute partially decayed vegetation and cause the high concentration of dissolved aquatic humus. In this case, the Secchi disk depth cannot be used to indicate trophic state because it is not a measure of phytoplankton crop. Other indicators, such as total phosphorus, chlorophyl, and the abundance of blue-green algae indicate a highly eutrophic state for Cullaby Lake. It should be noted that this is largely a natural condition for this lake, and adverse cultural influences are minimal.
Associated with the high nutrient content, Cullaby Lake has two serious problems that restrict use and appreciation: summer algal blooms and dense beds of macrophytes. On occasion in summer, the blue-green algae grow to such a large population that the shoreline accumulates piles of "green paint" (predominant blue-green genera are Aphanizomenon, Anabaena, Anacystis). This deters participation in water contact sports, which are normally very popular, and creates unpleasant odors. The phytoplankton are mostly diatoms during the spring and fall (Melosira granulata). During winter, cooler water temperatures supportpredominantly cryptomonads (Cryptomonas). The phytoplankton sample collected on 4/17/82 showed two species of algae to be more abundant than Cryptomonas; however both of these algae are quite small, and the
biomass was dominated by Cryptomonas. Other phytoplankton samples not reported here show that this successional pattern occurs year after year. Nearby houses are connected to a sewage treatment plant, thus should not be contributing to nutrient levels. The nutrients supporting the algal blooms are derived from the adjacent marshes, a natural source which would be difficult to control by artificial means. The shallowness also allows nutrients to be resuspended from the mud sediments. Future control of these algal blooms seems unlikely.
Likewise, the macrophytes are not easily controlled. They are found along nearly the entire perimeter of the lake and create the greatest problem in the narrow channel at the north end which connects the main lake with the permanent residences. At present, each season's crop of macrophytes are kept from totally choking the channel by the action of boat motor propellors cutting off the tops. Future control may be feasible in this relatively small channel by the use of fiber glass screens, herbicides, or some other technique that may be investigated. The macrophytes are probably light limited in the central areas of the lake although the maximum depth is only 12 feet.
Cullaby Lake is slightly acidic most of the year (pH less than 7.0, usually 6.5). The concentrations of major ions and the conductivity are above average for coastal lakes. Both alkalinity and conductivity are lower in winter and spring, but increase in the summer and fall. This seasonal pattern may well be due to the more rapid rate of flushing in the wet winter season as compared with the summer.