The Feeder Streams in More Detail
(Many of the conclusions about the current conditions of the major feeder streams come from Jim Ryan's May, 2013, site visit report. That report is catalogued as Appendix 3. See Appendix 1 for maps of the Porter, Tate and Cemetery Brook watersheds.)
Porter Brook is located at the northeastern corner of the lake. Its watershed is approximately 2.3 square miles and its linear length is approximately 2.3 miles, making it by far the largest of the feeder streams.
The brook begins in gently sloped agricultural land adjacent to Gebbie Road, and then flows westward toward the lake down a steep wooded hillside. The gradient flattens after Craftsbury Road as the brook meanders toward the lake. Part of the area between Craftsbury Road and the lake is a mapped Class Two wetland. Much of this area is accessible to the public via Highland Lodge's Porter Brook Nature Trail.
There is an open bottomed culvert where the brook crosses underneath Craftsbury Road, which allows for unimpeded passage of aquatic organisms and which is in good condition.
An unnamed brook feeds into Porter Brook from the southeast, just below Craftsbury Road. The brook originates on the western slope of Barr Hill, and flows westward toward Gebbie Road, and then turns southward until it joins with Porter Brook. For purposes of identification, it will be called West Barr Hill Brook.
According to several sources, this brook seems to be adding sediment to Porter Brook.
David Smith, who owns the land around the lower reaches of Porter Brook, has noted significant sedimentation over the past several years, which he attributes to runoff from Gebbie Road via West Barr Hill Brook, and to winter sand being washed from both Gebbie Road and Craftsbury Road. David has observed that the streambed of Porter Brook seems to be filling in in some areas; places which once had a rock and gravel bottom have now become soft silt.
In her 1997 report, Susan Warren noted significant erosion along West Barr Hill Brook. Jim Ryan also noted erosion in this area during his 2013 observations.
There is a significant delta where Porter Brook enters the lake. Photographic and anecdotal evidence suggests that the delta has grown in recent years. See Appendix 8L for photographic evidence of a recent sedimentation deposit on the delta.
That said, Porter Brook is in very good health, in no small part due to the extensive protections provided by the Porter Brook Natural Area.
Porter Brook is a vital cog in the Caspian Lake fishery, particularly for the lake's rainbow and brown trout populations. Rainbows migrate far up the brook to spawn in the early spring; browns spawn in the fall, when they will take advantage of a spate, move upstream, spawn, and leave quickly before the water level falls. It is likely that smelt and suckers also spawn in the brook in the spring. Fish and Wildlife personnel electrofished Porter Brook in 2007, and noted abundant juvenile trout populations, including small brook trout, most of which probably do not migrate to the lake.
Tate Brook is located on the middle of the north shore. The brook is the combination of Tate and Wright Brooks, which join approximately .25 miles north of the lake. Its watershed is approximately .5 square miles; its linear length (which includes Wright Brook) is approximately 1.5 miles. The area between North Shore Road and the lake was once far more wooded and boggy, but was Areclaimed@ approximately 50 years ago by the Watson family.
Both Wright and Tate Brooks form in higher elevations above Caspian Lake. After their confluence, the unified brook meanders slowly along flatter ground through beaver ponds and a wooded area until it crosses under North Shore Road through a culvert. There is no development in this area.
Part of the area north of North Shore Road is a mapped Class Two wetland.
The culvert under North Shore Road is tilted above stream level on the downstream end, which compromises the passage of aquatic organisms, particularly during normal and low water flows. Directly below the culvert is a deep pool which is an important spawning area for smelt, which usually congregate in the pool to spawn just after ice-out, often at night.
Below the culvert, the stream appears to be channelized, perhaps as the result of the Watson reclamation project. There is inadequate riparian buffering along this stretch.
Where the brook enters the lake there is a noticeable delta, which expanded dramatically in 1999 after a 100-year storm (See Appendix 7.). Photographic and anecdotal evidence suggests that this delta was quite large many years ago and was known as the Watson Sand Bar (see Appendix 8A). The bar was eliminated as part of the Watson reclamation project.
Fish and Wildlife personnel electrofished Tate Brook in 2007, and noted a modest juvenile trout population, some above the culvert.
Some of the existing studies suggest that Tate Brook is the least healthy of the three major feeder streams. However, most of these studies were conducted in the late 1990’s when some very aggressive logging near the brook combined with two serious storms to produce an unusual amount of sedimentation. Although there is still sedimentation, it is less dramatic than it was in the late 1990’s.
Cemetery Brook is located at the northwestern corner of the lake. Its watershed is approximately one square mile; its linear length is approximately one mile. The brook originates west of Lake Shore Road, above the Greensboro cemetery. It crosses under the road through a culvert, and then proceeds toward the lake down a gentle and diminishing grade. It appears to have been channelized in its upper reaches below Lake Shore Road because it is very straight for a stream of its type.
Several field drains feed directly into the brook in this area, which increases erosion and water flow during storm events.
The brook then enters the lake after a slow flat meander through alder thickets. A significant delta marks its entrance to the lake. This delta has increased in recent years, and at this point impedes direct access to the stream. Long time residents can remember rowing straight from the lake into the brook without being grounded by the shallow water of the delta.
Jim Ryan noted that the header of the culvert under Lake Shore Road needs repair.
Although the stream habitat seems favorable for spawning, there have been no recent studies or official observations of spawning activity in the stream. However, long time Greensboro residents remember observing large numbers of smelt and suckers spawning near the mouth of the brook during the spring.
A cluster of Japanese Knotweed has taken hold in the brook’s northwestern drainage near the intersection of North Shore Road and Lake Shore road. There is no evidence that it has migrated any further down the drainage.
Bachelor Brook, so called, is a small brook located just to the south of and parallel to Cemetery Brook. Its drainage is approximately a quarter of a square mile; its linear length is approximately one mile. Its source is a stilling pond situated to the west of Lake Shore Road.
There is evidence that the banks of this stream have not stabilized, except for the approximately one hundred feet where the stream enters the lake. The channel above this area has degraded, causing bank erosion and sedimentation. There is a growing delta where this stream enters the lake. Some domestic drainage systems seem to be adding to the erosion.
Numerous small fish, species unknown, have been observed in the pool directly below the culvert under Lake Shore Road.
Baker Hill Brook, so called, is located on the eastern shore of the lake, entering the lake just to the north of Black's Point. Its drainage is approximately a quarter of a mile; its linear length is approximately half a mile.
Very little information is available for this brook. In her 1997 visit Susan Warren noted only minor sedimentation.
Intermittent Brooks and spate brooks are scattered around the lake and are sometimes no more than drainage ditches. However, some of these brooks have caused serious erosion problems over the years; Lori Barg's 1999 study directly addresses this issue. Over the past twenty years, some intermittent brooks have begun to build significant deltas. Residents of the west shore have reported aggrading deltas near the south end of Aspenhurst (see Appendix 8, N,O, and P) . Susan Warren, in her inspection of the lake in 1998, confirmed this observation. Lori Barg characterized the aggrading of some of these deltas as severe
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