Perry Ridge: An Inherently Unstable Landform
Perry Ridge is a long, steep, wet mountain surrounded by water. On tile main Slocan Valley side lies the Slocan River. On the back of the ridge the Little Slocan River runs parallel to and meets the Slocan River at the south end of Perry Ridge. On the northern end the ridge comes down to Slocan Lake. This creates a dome-like structure 15 miles long, 5 miles wide and up to 6800 feet high.
On the side of the Slocan River, numerous small creeks have fostered small settlements and farms the whole length of the ridge. The slopes above the Little Slocan River have been heavily logged up into steep, wet areas. The Little Slocan attests to the increased run-off and sediment load each spring, as it pours its brown water into the main Slocan River.
The top of Perry Ridge is a wetland area that is rare if not totally unique in the whole valley. It is more or less flat and has many clearings with bogs, marshes, and ponds with lily pads. Although little studied, it is expected to be very rich in biological diversity. It has some of the valley's last old growth.
The watersheds have headwater bowls. The Ministry of Forests wants to log the front faces, the headwater bowls, the top and the back of the ridge. The road building and logging plans are under the Small Business Program. They include building 21 kilometres of road over five years, much of which would cross the headwaters of many creeks.
The proposed road which is currently the subject of a protest crosses the back of the ridge, above the Little Slocan River, and will increase the impact of sedimentation. The road location has been studied by expert hydrologist J. Allan Isaacson, who says the road crosses a steep area where it could cause landslides into the river. This road crosses over to the front side of the ridge, and will be used to access planned logging on the front sides.
The Isaacson report issued grave warnings against any logging or road building on the front side. Isaacson said some of the previous hydrology and terrain stability reports done for Slocan Forest Products on Perry Ridge used incorrect' assessment procedures, contained inaccurate information, overlooked some important aspects, and recommended procedures to protect water that would be ineffective, given the' terrain.
Isaacson Hydrology Report, February 1994:
"In my opinion, logging the Perry Ridge mountain system would result in irreparable damage to the valley below and to the water users' systems. There may be some sites in the upper basins that are stable or flat enough to be logged. However, to get access to these areas would mean crossing some very unstable slopes that are at the headwaters of very steep entrenched streams... Sixty percent of Perry Ridge is high to extreme hazard rating for sediment yield or induced mass wasting (landslides). These basins are directly above 56 licensed water sources. There are many' sites of natural 'mass wasting and avalanche p9ths... It, is important to remember that 'road locations' and logging are planned above very steep gradient streams that are going to bring any sediment or mass wasting directly to the valley floor. In summary, I would recommend against any road building or logging activity on Perry Ridge."
A Naturally Unstable Land
A large portion of the snowmelt and rainfall on the top of the mountain drains underground to the river. The area where the steep slopes meet the valley bottom is very unstable. Last year, a house near the river in Winlaw had to be evacuated after a crack opened up in, the ground, ran beneath the house parallel to the river, and split off a large piece of land which subsequently sank, leaving a steep cutbank. The crack is now at least 1.5 km. long, and other houses are threatened. There are also cracks around the nearby bridge. A portion of the river which used to be about 14 feet deep is now an island. Six kilometres down the road, there has been another massive slump, this one 30 feet deep.
Logging and road-building could have powerful impacts because of this natural instability. The Ministry of Environment brought in one of the government's top hydrologists, Doug VanDine, last year. He said extensive studies were needed before any logging on the front side of the ridge. The studies have not been done, yet the road-building for the logging is going ahead. The government has acknowledged that once the road is built1 there will have to be logging to pay for the road. The logging on the front side of the ridge will also require a net-work of roads.
This spring, landslides from private land logging on Perry Ridge repeatedly came' down on the main access road for people living along the river at the base of the ridge. School buses travel this road. The government is knowingly endangering people's water, homes and jives by allowing Perry Ridge to be logged. Our government is not concerned enough about people's homes and lives to even do the hydrological investigation recommended by Mr. Van Dyne before permitting logging activity.
VanDine Terrain Stability Report, December 1996
"Most of the tributary streams that descend the east slope of Perry ridge between Lemon Creek and Winlaw are prone to debris flows. I observed several residences that are located on the alluvial/colluvial fans at the bases of' these streams. I recommend that the residents in the valley should be made aware of the potential for debris flows
To better understand the correlation between surface water and groundwater in the valley bottom, I recommend that a hydrological study of the valley bottom, investigating the surface water and groundwater flow patterns, be undertaken ... Future logging on 'the east slope of Perry Ridge should only be carried out after all potential downslope and downstream effects are considered."' (Emphasis added).
Why the Slocan Valley Needs an Ecosystem-based Plan
The health risks of watershed logging, and the problems it causes in water lines, are well known, serious concerns. But they tend to be focused upon individual, small streams that provide drinking water. While it's under-stood that the effects of roads and logging on these small watersheds are cumulative, virtually zero attention is paid to how the impacts on many of these small watersheds are multiplied as they accumulate downstream in the larger creeks, the river, and the lake.
We often think of the Slocan Valley as an unusually intact forested valley. But that's because the huge clearcuts in our side valleys are out of sight. There have been many landslides caused by roads and clearcuts. It is unfortunate, however, that the dramatic impacts get more attention than the simple erosion which accumulates year after year from clearcuts and roads throughout the whole drainage basin. The fact that eroded sediment alters stream beds and river channels, and accrues downstream with the eventual result of flooding, is little known or looked after. These are impacts which cannot be appreciated on a cutblock-by-cutblock, or on a watershed-by-watershed scale.
For the last few years in the USA, the consequences of many years of clearcut logging and road building have accrued into disasters: massive floods, hundreds of homeless people, damaged roads, fish habitat wiped out on a massive scale. In the Slocan Valley, a large portion of Slocan Valley residents live along the river. They are keenly aware that they will bear the consequences of the accumulated road building and logging in ever water-shed upstream from them.
Many clearcuts in the valley are only just now reaching the age where water runoff starts to accelerate due to the rotting of tree roots. Creeks flowing brown with silt washed down by landslides are an indication that Slocan Valley inhabitants may already be sitting on a hydrological time bomb. If we aren't now in such a situation, we soon will be if the five-year Forest Development Plans and proposed woodlots are approved.
This is why logging and roadbuilding on the back side of Perry Ridge is a concern, in addition to the logging on the front side where most of the water licences are. It is also why many residents, when asked what can be done to resolve the severe conflict in the valley, would not be likely to answer, "Save New Denver Flats", or "Save Perry Ridge". Instead, they would say, "We need an ecosystem-based plan for the whole valley."
This information has been complied by the Valhalla Wilderness Society from various reports photographs and first-hand observations provided by several Perry Ridge water users.