Notes of Innis Creek Road and a View of the Twin Sisters Dunite

Innis Creek Road is a patched up bit of road that frequently is flooded by water backing up in the swampy ground the road crosses. With the dry warm weather, the road was not covered with water.

This stretch of road crosses a short-lived former path of the late ice age melt water channel that cut through the terrace between what is now the South Fork Nooksack River valley and the upper Samish River valley.

On clear days this area of the Samish/South Fork Nooksack provides a great view of the Twin Sisters Range.  

The Twin Sisters consists of a fault bound block of dunite. The dunite is mostly olivine that has weathered to a distinctive orange color. The ridge reaches about 7,000 feet. The combination of very heavy winter snow and poor growing conditions for plants on olivine rocks gives this mini range in the Northwest Cascades a distinctive look.    

Resilient Arbutus menziesii

Arbutus menziesii (madrone) have a preference for sunny dry spots and hence are a common tree along shoreline bluffs often growing along the bluff edge. That habit means they do fall off the bluffs. But their tolerance for drought conditions and disturbance allows for survival and even thriving under extreme conditions of nearly being uprooted as demonstrated by this tree.     

Another nearby tree had recently broken off due to the structural strain along with some wind but was still alive sending up new growth from the broken off trunk. I have seen this same habit in burned over areas with madrones and sites where madrones were cut down.

Geology note: in the above image the base of the bluff is sandstone bedrock overlain by glacial drift. 

Notes on ".....everything west of I-5 will be toast"

First - note that ".... everything west of I-5 will be toast" is not the full the quote.

Kathyrn Schulz's article in the New Yorker (newyorker.com/the-really-big-one) managed to do more to get attention about the big subduction quake risk on the Washington (and Oregon and southern BC) coasts than any article. I became aware something was up in our internet age media when a post I put up regarding tsunamis three years ago started getting 200 to 300 page views a day. The fact that it took an article in the New Yorker to create such reaction has to be a bit frustrating to geologists and emergency planners that have tried to raise attention to this risk.

Chris Goldfinger, a geologist heavily relied on for the article put up a post  (the-meaning-of-toast) regarding the "toast" quote in the article that is consistent with my take on the quote. I will only add that it is my experience that emergency planners tend to be way ahead of land use planners when it comes to geologic hazards. One could take the view that land use planners lack of corrective action as geologic hazards become better understood are creating the emergencies that emergency planners are then forced to address.     

Kathyrn Schulz also had an excellent follow up article on the initial article including some maps regarding seismic shaking from the "big full rip" earthquake scenario (how-to-stay-safe-when-the-big-one-comes). The maps that were not part of the initial article perhaps clarifies the risk.

I also heard an interview of Ms. Schulz. She, along with Dr. Goldfinger and numerous geologists I have spoken with as well as myself, has feelings of dread whenever visiting the outer coast of Oregon. The same feeling is present when I have visited the outer coast of Washington. The "big one" will shake the outer coast much more intensely than the I-5 corridor and then will be followed by a very large tsunami. Having visited outer coast tsunami sites it is a hard thing to be in communities that one knows face nearly complete destruction. Those places face hard planning both for land use and emergencies.  

Nagasaki and the Washington Landscape

Missed posting this by a day as I was out in the field (yes, on a Sunday).

Above Nagasaki, Japan August 9, 1945 (Photo by Charles Levy)

Fission material for the first nuclear detonation (Trinity nuclear test) and the fuel for the second second atomic attack on Japan was made at the Hanford site north of Richland, Washington.

View from the east of one of the remaining atomic weapons nuclear reactors at Hanford

Columbia River between plant and photo shot with Rattlesnake Mountain the ridge in the distance

 The nuclear weapons fuel production left a significant mark on the landscape. Of course there is the waste legacy that continues to vex agency and state officials. The contamination also is a source of long term jobs for the area. The town of Hanford is long gone having been condemned along with the farmland in the vicinity. A large portion of the Hanford weapons site is now a National Monument. The presence of the nuclear plants precluded the construction of a dam and hence this is the only reach of the Columbia River in Washington State without a dam polling the water. 

Washington State Senator Doug Ericksen Fails to Protect Farms and Businesses

State Senator Doug Ericksen represents the 42nd Legislative District. The district covers most of Whatcom County minus a big chunk of Bellingham. The district is a mix of small towns with the largest area of farmland in western Washington as well as mountain slopes covered with forest land. Mr. Ericksen failed his district very badly and intentionally during the last legislative session.

Threats to farmland and timberland are often equated with development. However, by far the largest threat to farmland acreage in Whatcom County at the moment is the Swift Creek landslide. I've posted about the slide numerous times and even gave it its own label if you want to see all the posts.

The big problem with the Swift Creek landslide can be summed up with a few images:

Asbestos form minerals from within the landslide material

 

The landslide failure is within deeply weathered serpentinized bedrock that is full of asbestos form minerals. And there is a lot of landslide material sliding down the west slope of Sumas Mountain.

 

Lower end of Swift Creek landslide

View across the lower end of the slide

One estimate on the volume of sediment being delivered to the base of the mountain by this ongoing landslide is the equivalent of one football field buried 100 feet deep every year.

Swift Creek flowing across the Sumas Valley floor

 

The problem below the slide is that the low stream gradients on the valley floor cause Swift Creek's channel to become plugged with sediment. This presents a problem at stream crossings.

Swift Creek at Goodwin Road

And on farmland.

Dredge piles along the banks of Swift Creek

The above image can only partially capture the problem. So much sediment has accumulated that the creek bed is elevated above the surrounding farm fields.

There is another issue besides the asbestos. The sediment is derived from fractured serpentine rocks. This rock type has some unique chemistry and is well known wherever it occurs to be very hard on most plants. The metals ratio of calcium and magnesium cause plants to have problems, the pH is elevated and there is a lack of phosphate bearing minerals, phosphorus being an element essential to life.

Note the bare sediment piles in the images above. Nothing can grown on these piles. So besides the asbestos problem as a health risk issue, the sediment is essentially toxic to farmland soils. Notes on USDA soil mapping of the area mark areas that have been impacted by Swift Creek sediment from past floods caused by sediment filling the channel of the creek. With nothing being able to grow the sediment is subject to being blown about as dust containing asbestos fibers.

The extent of the problem is partially shown in this Google earth image:

 

Swift Creek empties into the Sumas River. The Sumas River itself is a slow stream flowing through an area of low gradients and the added sediment is causing reaches of the Sumas to fill with sediment. Flooding on Swift Creek and the Sumas River spreads sediment that is essentially hostile to life as well as full as asbestos fibers over farm fields, and where the Sumas River flows through Nooksack and further downstream through Sumas onto residential properties. 

 

For a period of time the county dredged the creek at no small expense and sediment from the piles was hauled off by locals for use as fill, for surfacing driveways and roads and in at least one case as a fill for a state highway embankment. A sawmill property on the north side of the creek became concerned about flooding and began a routine dredging operation to maintain the channel away from the mill site.

 

All that asbestos containing material being dug up and moved around eventually got the EPA's attention which led to the Army Corp of Engineers no longer issuing permits for dredging the creek. Permits have been issued on an emergency basis as there are major roads that would be closed and uncontrolled flooding and sediment deposition has been recognized as a major problem that would also pose a significant threat.  

 

This is where Doug Ericksen comes in. Whatcom County, the EPA and the Washington State Department of Ecology all recognize that the Swift Creek sediment needs to be managed. Allowing continued flooding and Swift Creek to flow unmanaged over large swaths of land poses a huge health risk and a huge economic loss to farms, businesses and property values. The old way of dredging and allowing the sediment to be spread with no controls is simply not acceptable under current federal law. After a lot of hard work and study an approach to managing the sediment was figured out and the governor put the funding in the State budget proposal to the state legislators. The budget item passed in the house with support by both 42nd house members Vince Buys and Luanne Van Werven.

 

Doug Ericksen is a high ranking State Senator with substantial authority. This should have been a no brainer, but the budget item for supporting the sediment management of Swift Creek was removed from the budget. Doug Ericksen did that and in that regard has intentionally failed his constituents. Whatcom County is left with a huge expense to maintain the creek flowing under the bridges and not burying large swaths of farmland. Several square miles of farm land are now at substantial risk of being lost. A saw mill on the north side of the creek will be at risk. A mushroom farm south of the creek is at risk. Those two businesses alone are over 100 jobs. The towns of Nooksack and Sumas are at risk and their growth plans now face uncertainty. Property owners face substantial loss in value of their land.   

 

I can only speculate on Doug Ericksen's motives. Perhaps he has allowed his ideology regarding environmental regulation to cloud his judgment. He presumes that the EPA rules on risks from asbestos are groundless and is willing to allow farmland, businesses, two small towns and property owners to suffer the consequences. Or he has simply been too taken up with his position of power at the State level to bother getting his head around a very real and major problem within his own district.

 

Regardless of the speculation as to Mr. Ericksen's motives or reasoning, he has very badly failed the citizens and businesses of a significant portion of the district he represents.    

Gibralter Road Landslide

Along the south shore of Fidalgo Island is a series of deep-seated landslides. The best known slide is the Gibralter Slide named for the road that crosses the landslide. Dave Wenning has an excellent perspective on the slide at fidalgoweather.net/2012/04/gibralter-road-landslide.html.

I have done a few projects on or in the vicinity of this slide complex. My initial projects were done pre LiDAR; however, the LiDAR simply confirms what was alreday generally known about this slide complex. But it sure makes it easier to visualize. 

LiDAR image of the Gibralter Landslide

The LiDAR resolution is not very high, but it is good enough to get a handle on the head scarp of the slide complex and the various somewhat coherent blocks within the landslide complex. The slide complex continues to the northeast but as far as I know the slide activity to the northeast has been minimal or not reported. 

The Washington Coastal Atlas (1978) indicates that the subject property is located on an area of unstable shoreline.  Areas mapped as “recent unstable areas” are indicated to the east and west of the subject property. I have heard verbal reports of some slide movement in the 1960s including slide movement during the Seattle earthquake. 

After slide movement in 1990 and 1991 the slide stability was assessed by GeoEngineers in a report entitled Geotechnical Evaluation, Gibraltar Road Landslide, Fidalgo Island, Skagit County in 1991.  Six borings were drilled through and adjacent to the slide complex. The report concludes that the movement of the slide in 1990/1991 was a re-activation of an ancient landslide complex due to extremely heavy precipitation.  The report indicated that the slide movement of between 1 and 4 feet took place and moved not as a contiguous solid mass but in discrete blocks within the landslide complex. This is consistent with pictures I have seen as well as my own observations of some of the slide blocks within the landslide. The final determination of the report indicated that the slide is slow moving and is unlikely to endanger human life.  Recommendations were made including setbacks from the slope scarps within the landslide complex and preparation for differential settlement on the slide mass.  The report also indicated that reducing stormwater infiltration into the slide and reducing erosion at the toe of the slide would reduce the potential unstable conditions.

Since the GeoEngineers report some additional development has taken place on the landslide area. In addition some additional substantial shoreline armoring has taken place along the shoreline such that the erosion at the toe of the shoreline bluff slope has been essentially eliminated. Stormwater drainage has since been added to the area including drainage improvements on the upland areas above the landslide complex that routes water via tightline pipes to the shoreline versus onto the slide area.   

LiDAR  imagery provides a visual picture of the deep-seated area. The imagery does show that there are discrete blocks within the landslide complex. An aerial view of the site and vicinity is also provided below with edges of blocks. 

Head wall scarp of the landslide north of Gibralter Road

Coherent slide block showing classic back rotation

headwall of slide is to the right and shore area is a few hundred feet to the left

While some homes on the slide have been designed to anticipate the potential fro movement some have not. However, the erosion protection at the toe of the slope along the beach (see DW's post for good pictures) has improved the stability and the stormwater management has likely helped as well. 

The overall stratigraphy consists of older laminated silts and clays overlain by advance outwash overlain by glacial till and then recessional marine deposits. However, these units have been disrupted by the presence of a deep-seated landslide. 

Its the older clays at the base of the slide that are the slide culprit. I suspect some of the clay is pre glacial and the tectonic strain of the clays being loaded with ice and then unloaded may have created failure areas in the clay. I should add this area is also along a line of faulting that could also have fractured the clay beds in a manner that could lead to sliding.

The units and the slide are somewhat similar to the large Ledgewood Slide on Whidbey Island. Only here the shoreline erosion rate is much lower and the overall aspect is lower in elevation and steepness.   

Geology Underfoot

I have been a bit slow to acquire David Tucker's Geology Underfoot. And hence a bit slow to say anything about it. DT has assembled a series of geology excursions for western Washington with a level of detail and accuracy that is impressive. 

The cover of the book is a spectacular image of what a future Mount Rainier eruption may look like. The image warps around the book to the back. Orting, Sumner, Puyallup, Fife and the Tacoma waterfront will have some trouble with Rainier. 

IDT has to do what every geology guide book does - that is provide an introduction to geology and the big picture geology of the area with plate tectonics and what comes after. I always enjoy reading these sections, not to really learn any geology but to see how different geologists tackle the subject with a limited amount of pages. DT did the task about as well as any I have seen with some very good graphics and without fear even throwing in the complication of Baja BC for hard core tectonic folks. This section was not overly dumbed down.

The book provides 22 geology excursions with detail on how to get there and what to see. A good diverse selection to get a good taste of the diverse geologic features in western Washington. I went right to some of the places I have been to.

I believe DT provides the best write up I have seen on the Mima Mounds - site and subject that drives geologists crazy. DT runs through all the various theories and problems with all of the theories and includes even the latest ideas and observations. If you have any intent of visiting the Mima Mounds or trying to solve the mounds, you would be well advised to take a careful read of this trip.

The Bridge of the Gods, where a massive landslide blocked the Columbia River was well researched and fully up to date. Cheryl Staryed did not provide much in Wild: From Lost to Found on the Pacific Crest Trail. But DT will fill you in on the compelling story of this remarkable location with a very good historic perspective.

A good geology book to western Washington has been long overdue. DT provides it. There is a enough detail and explanation in each excursion to ensure that anyone that takes the trip with book in hand will learn something. That includes geologists and non geologists alike. And for geologists dragging friends along on excursions a great way to impress your friends.