Flood Plain Hazards of Open Pit Mines

I missed the historic heatwave in the Pacific Northwest as I am currently in Germany. I am not in the zone that has been impacted and terrible floods, but the event is 'close to home' so to speak. Dave Petley (HERE) noted a river in the west of Germany that broke out of its course and flowed into an open pit coal mine in Inden. 

Dave noted the river course into the mine followed an old channel. That channel was the former river channel up until about 15 years ago. The channel was blocked and the river was rerouted in a long circuitous route around the mine.

Blue line shows river route around open pit coal mine

Blue line showing most recent river route and red line showing former path

Although the flooding of the coal mine was impressive, a more dangerous flood into an open pit mine took place a few miles away at Blessem. NPR led their story on the flooding with an image that had a caption about an entire field collapsing due to flooding (npr.org/germany-belgium-flooding). 

  (picture alliance/dpa/Rhein-Erft-Kreis | Rhein-Erft-Kreis) The image shows very rapid headward erosion as floodwaters drain off the flood plain down a steep gradient. The source of that gradient was and open pit sand and gravel mine. 

Same site looking toward the mine  (picture alliance/dpa/Rhein-Erft-Kreis | Rhein-Erft-Kreis)

Red line is approximate extent of area eroded. The yellow line is my measurement of the headward erosion distance of 850 feet.

The headward erosion continued after the above image and expanded into the town taking out a number of buildings. 

 

In this case it appears that flood waters on the flood plain began to flow rapidly towards the pit as the water drained towards the low area of the sand and gravel mine. While gentle slope wide flood plains have flood risk and potential hazards associated with channel movement. The rapid erosion associated with flood water flows into open pit mines is well demonstrated at this site.    

Notes on Heatwave Global Warming Attribution

Phillips and others (2021) have taken a rapid assessment run at global warming attribution of the 2021 Pacific Northwest heat event. A summary of key points is provided at the beginning of the paper. Two points stand out:

The observed temperatures were so extreme that they lie far outside the range of historically observed temperatures. This makes it hard to quantify with confidence how rare the event was. In the most realistic statistical analysis the event is estimated to be about a 1 in 1000 year event in today’s climate.

This simply emphasizes what most long-term Pacific Northwest residences felt - this event was very far from what anyone expects for northwest summers. For those that experienced the event, you have a story to tell. But this was more than a remarkable event for the Pacific Northwest; Christopher Burt author of Extreme Weather stated “This is the most anomalous regional extreme heat event to occur anywhere on Earth since temperature records began. Nothing can compare.”   So for those that went through the event (I missed it), you can say you went through a world historic weather event.

There are two possible sources of this extreme jump in peak temperatures. The first is that this is a very low probability event, even in the current climate which already includes about 1.2°C of global warming -- the statistical equivalent of really bad luck, albeit aggravated by climate change. The second option is that nonlinear interactions in the climate have substantially increased the probability of such extreme heat, much beyond the gradual increase in heat extremes that has been observed up to now. We need to investigate the second possibility further, although we note the climate models do not show it. All numbers below assume that the heatwave was a very low probability event that was not caused by new nonlinearities. 

Under the first possible source, that the event was a very low probability event, global warming additive attribution pushes the temperature upward some amount more. Phillips and others (2021) note that the observed annual maximum daily temperatures in the Pacific Northwest trend is approximately 2 times the global temperature trend. So regardless of the event being rare, our heatwave temperatures have been trending upward at a greater rate than the global temperature trend as well as our local temperature trend.

Figure 4 b) Annual maximum of the index series with a 10-yr running mean (green line)

Burt noted in 2017 that Seattle has had 122 record high temperatures since 2010 compared to 19 record low temperatures and Salem has had 98 record highs compared to only 11 record lows.  

Another potential added source of heat is the trend of 500hPa height associated with a warming expanding atmosphere (Christidis and Stott ,2015). 

Phillips and others (2021) also suggest a source of added heat may be from persistent drought in the west leading to higher temperatures.

Given the circulation associated with major heatwaves in the Pacific Northwest, drought and enhanced heating in the southwest will be a contributing factor as hot air from that region descends into the lower elevation areas of eastern Washington and across the Cascades to the west side. 

Phillips and others (2021) suggest that global warming pushed the temperatures about 2°C warmer than they otherwise would have been. 

The other question or cause would be the potential that the heatwave was caused by a 'nonlinear' factor related to global warming. Phillips and others (2021) do not attribute this event to a nonlinear event such as a wavy stalled jet stream, but do give it a brief discussion and suggest further analysis. 'Stuck' jet streams or omega blocks are a point of some debate in climate science. 

I would note that this attribution paper was a bit narrow. John Pollack (HERE) notes that this event was preceded by two western US heatwaves of similar pattern, but to the south in June that set records including tying the all time high temperature in Palm Springs, CA of 123 F. Those events likely provided some additional heat charge to the third high pressure event centered in south British Columbia with southeast flow of air coming up from the southwest U.S into the Pacific Northwest. And the pattern of high pressure heatwaves of long duration is continuing. From the National Weather Service: The current forecast for Las Vegas is just below the all-time record of 117.  This is the fourth western US major/record breaking heatwave in the past month.

A Few Notes and Readings on the Heat Wave

I missed the heat event in Washington as I am out of the area. So I have no direct observations about the event. From afar it was really remarkable to follow this event as it developed. The weather models and projections were alarming and I will say it caused a level of concern for friends and family. I will also add that I have spent a fair bit of time in the Fraser River canyon and it is is painful to think about what has happened in Lytton.    

First of all, the weather prediction models were amazing. Models can be useful, but it really is remarkable when the models indicate something that has never happened and is an extremely rare event and the actual event happens as the models indicated.  

Phillippe Papin via twitter.com/pppapin/ lays out the antecedent event in the tropics and how the extreme heat would be generated. Note the post was June 23.  

There were a few statements made during the run up to and after the event that warrant repeating:

From the National Weather Service Seattle Office as the heat event was about to take place:  "As there is no previous occurrence of the event we're experiencing in the local climatological record, it is somewhat disconcerting to have no analogy to work with." --- National Weather Service, Seattle on June 27, 2021. 

This statement from Bob Henson and Jeff Masters clarifies what a big deal this heat event is: "Never in the century-plus history of world weather observation have so many all-time heat records fallen by such a large margin than in the past week’s historic heat wave in western North America. The only heat wave that compares is the great Dust Bowl heat wave of July 1936 in the U.S. Midwest and south-central Canada. But even that cannot compare to what happened in the Northwest U.S. and western Canada over the past week.", Bob Henson and Jeff Masters (worlds-most-extreme-heat-wave-in-modern-history)

Jeff Beradelli (Here) -- "To put climate extremes into perspective we measure against the average. The sigma is the standard deviation of a normal distribution of expected values. In this case the heat dome sigma max is 4.4 - that means it's outside of 99.99% of expected values or a 1/10,000+ chance.

 Bumbaco, Dello and Bond (2013) describe of how most heat waves develop in the Pacific Northwest and that description is consistent with this latest event. They note "Current research suggests that the frequency and duration of heat waves are expected to increase in much of the United States, and analysis of the heat events reveals that a significant, increasing trend in the frequency of the nighttime events is already occurring in the Pacific Northwest. A heat wave occurred in 2009 that set all-time-record maximum temperatures in many locations and ranked as the second strongest daytime event and the longest nighttime event in the record."

This chart shows that since the 2013 above described paper there have been a number of additional heat evets of 20+ above normal, and this event blew way past what took place in 2009.  

The attribution of this event to anthropogenic global warming (AGW) will be analyzed in detail. The attribution of AGW to extreme heat waves has been generally strong (Special Supplement to the Bulletin of the American Meteorological Society Vol. 102, No. 1, January 2021).

Foster Creek Beaver Analogs

Foster Creek drains the north side of the Waterville Plateau. The creek has three forks that join together a few miles south of Bridgeport before discharging to the Columbia River just below Chief Joseph Dam and just east of Bridgeport. State Highway 17 follows the East Fork up to the glacier scoured upper northern part of the plateau. As the creek descends down for the glacial scoured upper plateau it descends through an area of glacial lake sediments deposited in the valley from the ice dammed Columbia River Martin (2001). The fine silts are subject to rapid erosion and over a stretch of the valley has formed a badland area (mini-badland-southeast-of-bridgeport).

When the creek reaches the glacial lake sediments, the creek is subject to forming deeply incised arroyos. Blanton (2004) discusses the complexity of arroyo development and riparian management along the West Fork of Foster Creek. 

One of the issues of arroyo development is the deeply incised stream lowers the water table along the creek except in the bottom of the arroyo. That reduces the width of the riparian zone and the beneficial habitat (note that the arroyo banks have beneficial habitats as well such as burrows for cliff swallows). The lower water table and narrowed stream channel also impacts down stream sections of the creek. More intense peak flows during storm events or snow melts can be one result or the reverse: a loss of storage in the areas of the lowered water table may mean lower flows in the dry periods. 

An approach to back up the water is to copy something that has been missing in the watershed. Jay guided me to a project on Foster Creek that is being used throughout the west -- a beaver dam analog.

Beaver dam analog

Stakes driven into the ground with woody debris weaved through them

Plane Notes: A Few Infrastructure Observations

Aerial views are part of my routine 'tool box' as a geologist. I use aerial photographs on a nearly daily basis for multiple reasons. Other aerial imagery is utilized as well - lidar, infrared and sometimes radar imagery. I enjoy this type of work and a there is a sense of discovery when viewing aerials. 

I had previously seen the below feature when reviewing historic aerials for a project, and hence, when I got a view of it while flying out of Seattle knew exactly what it was. 

Cedar Hills Landfill

The Cedar Hills Landfill serves King County. 

While I do like to see the geology observable while flying, the human infrastructure also stands out. Some infrastructure has far reaching influence.  

From right to left: Keechelus, Kaches, Cle Elum

Interstate 90 traverses along the left side of Keechelus

The Snoqulamie Pass ski areas are visible in the lower right 

The three lakes are all part of the Yakima River watershed. There were natural lakes at all three locations associated with past ice age alpine glaciers that left depressions and moraines in the three valleys. Dams were erected at the outlets of all three to raise the water storage which is then metered out through the summer growing season in the Yakima Valley below. The dams should not be considered static features - they require ongoing maintenance and at times repair. All three dams are Federal dams managed and operated by the Bureau of Reclamation.    

The western side of the Quincy Basin with the Columbia River to the right

The rocky ground with lakes are former spill ways from the large ice-age floods (quincy-basin-plumbing). The Quincy Basin is a major agricultural area in central Washington with irrigation water supplied via water routed from the Grand Coulee Dam through the former routes of the ice-age floods. On the upper part of the picture an additional flood spill way can be seen plus a whiteish area. The upper whiteish area is a site of a diatomite mine. The ice-age floods plucked off enough basalt to expose old lake deposits containing diatoms that are now mined.  

 

Moses Lake and Potholes Reservoir to the north

The east end of the Quincy Basin is drained through another ice-age flood route. Moses Lake is a natural lake formed in the deep flood water channels. Its depth and extent was slightly expanded by a small dam work at the outlet in 1911. Potholes Reservoir is formed by O'Sullivan Dam. The lakes receive natural water flow via Crab Creek, but the bulk of the water passing through now is via the water pumped into the upstream ice-age flood route of Grande Coulee and then routed via other reservoirs and canals to the Quincy Basin.    

Potholes Reservoir

Potholes Reservoir is a critical junction in the Columbia Basin project. Water from this area is routed to project irrigation lands around Basin City (upper left in the picture), the Crab Creek valley (above the lake in the picture) and the Wahluke Slope (dark area above the Crab Creek area and separated from Crab Creek by the ridge of the Saddle Mountains).

The lower Snake River

The lower Snake River is an area where infrastructure has generated some controversy. The lower Snake in Washington State has four dams that were the last of the big dams on Columbia-Snake system. These dams have led to the extinction of some salmon species and endangerment of additional salmon species. There is some irrigation near the lower Snake River. The big fields on the left are dry land wheat, but nearer the river above Ice Harbor Dam pumps in the backed up river and in wells near the river supply water to irrigated land. Part of the conflict over the lower Snake dams revolves around these irrigated lands --- if the dams are removed the irrigation works will need to be altered and water pumping costs may increase. 

Lower Snake River passing through the Palouse 

Most of the area along the lower Snake in Washington is not irrigated farm land as the river is a in a narrow steep rocky canyon for much of this river reach. The above image shows the slack water backed up by Lower Monumental Dam. The wide tributary is the Palouse River also backed up by the dam. The tributary on the left is the Tucannon River which drains out of the north side of the Blue Mountains.

The high Palouse and Blue Mountains

The further east position and higher elevation means wetter areas. In June the eastern Palouse and the Blue Mountains are very green landscapes. here the moisture levels are high enough that dry land winter wheat can be grown every year versus the every other year pattern in the areas to the west and at lower elevations. That switch over line can be seen on the right portion of the picture. 

If you blow up the picture above or better the one below another newer infrastructure feature can be observed. 

Rows of wind turbins line the upper ridges of the high Palouse in this area

One last infrastructure note beyond Washington Sate's borders: 

Surface mines along mountain ridges in southeast Idaho. 

Bear lake in northwest Utah is in the distance

Extensive open pit surface mining has been taking place in southeast Idaho over the past 50 plus years. The mines are phosphate mines. Some of that phosphate may end up shipped to Washington farm lands as a critical fertilizer. This particular mine is a JR Simplot Smoky Canyon Mine. The phosphate ore is mixed with water and pumped via pipeline for processing in Pocatello, ID. This was the best view I have had of the scale of the phosphate mining in this area. Its impressive on the ground, but more so from the air.   

Plane Notes: Carlson Lake Landslide in the Lost River Range, Idaho

My preference even for long trips is to drive. But some trips do require flying. Initially the landscape is familiar and then becomes semi familiar. Looking down at the Lost River Range of Idaho (slight familiarity) I spotted a large landslide.

Carlson Lake Landslide

The slide is about 2 miles long with a headwall at about 8,500 feet elevation and the toe extending out onto the broad alluvial fan at an elevation of 6,700 feet. The slide took place within andesitic and basaltic lava flow formations. 

Schaller (1991) analyzed this slide and obtained a radiocarbon date of 2,420 bp. However, Krueger (2014) utilizing Lake Carlson on the upper part of the slide for past climate analysis got an age date on the upper slide of 9,054 years. It is possible that the slide has had multiple periods of movement that would explain a younger age at the toe of the slide. The slide is located within an active seismic area - the Borah Peak Earthquake ruptured the ground over 21-mile long fault scarp on the opposite side of the Lost Creek Range.    

The trip was a long trip that involved 2 bus rides, 5 planes and 3 trains to get to the destination, but glad to have made it.

Skagit County Mine Woes

Complex of quarries that supply a community

Quarries for aggregate go through various phases on a local basis. Once a group of quarries gets established and the market supply is being met there is a period of stasis. But eventually the quarries exhaust the resource and new supplies must be found. Skagit County is going through one of those supply shifts and the disruption that goes with that change goskagit.com/opposition-continues-over-skagit-county-mining-proposals. The three proposed mine sites each has particular issues and regulatory status with the issues described in the article. Besides the three mines in the article another mine is proposed to expand, but apparently no significant objections have arisen yet and a fifth mine is in the early stages of the permit process. 

The State Growth Management Act includes language regarding resource land protection. Resource lands typically include farm land, forest land and mineral resources. The approach that counties have taken on resource land protection varies. For mineral lands, the protection limits the land use that can take place on the or near the areas of mineral resources with the idea avoiding loosing the resource to being covered homes. 

An example of an excellent source of sand and gravel lost to use is Mercer Island in Lake Washington smack in the middle of an area of high demand in King County.

Mercer Island

Obviously when Mercer Island was initially developed there were plenty of resources elsewhere and development of the island proceeded and one could argue that delaying development of the island so a big chunk of it could be mined would not be an ideal scenario. 

Skagit County took a very broad approach that utilized mostly geology to designate large areas of the county for mineral resource protection. There was some consideration of preexisting conflict so that some areas were pulled out of the protection zone. However, when mine sites enter actual permitting, it is very clear that conflicts are still present or issues still require attention. Just because an area is designated for protection does not mean a guarantee to be permitted to mine. 

And there have been Skagit property owners that have sought to do the opposite of getting a mine permit, getting the property removed from designation as a mineral area. This can be done by demonstrating that the site is underlain by sand and gravel or that other issues would preclude ever being permitted to mine. One site was removed after the Planning Commission agreed that the site could not be mined due to the presence of high voltage electric transmission lines and a large volume natural gas pipeline. I would note further that the site was also underlain by a thick layer glacial till that was mostly silt and clay.