Month: February 2017

  • Stormy Weather

    First, as an update to my last post, Oroville Dam is still intact, and the spillways are still damaged.  The lake has been lowered by using the main spillway as much as they dared -- the secondary spillway is no longer being used, and they have been working feverishly to repair the damage so it could be used again if necessary.  They are waiting until after this weekend's storm (which began today) to stop the flow on the main spillway enough to assess the damage.  Meantime,  today's storm has caused creeks to overflow, seriously flooding the city of San Jose, south of San Francisco.

    Southern California received more rain last weekend. causing major flooding in the coastal southern half of the state.  It was also extremely windy, and there were many trees downed throughout the area.  About two blocks from my home, there was a whole row of 35-year-old pine trees -- it seems every other tree was blown over!  It's not safe to stop and take shots of the trees, but they were big ones, falling over a main road.  I stayed indoors for 3 days -- by the time I saw the trees, they had been trimmed away from the road and the sidewalk, and people had taken some of the movable pieces, apparently for firewood.  I was able to get a couple of shots of damage nearby -- across the road from my home are a couple of visitor parking spaces, marked by a sign -- well, they were marked by a sign:

    IMGP0820-001

    And in a nearby strip mall, there is/was a realtor's sign advertising the availability of retail space.

    IMGP0821-001

    Today was the first dry day we've had for several weeks, and the sun was actually shining.  We expect one more day of similar weather, then it will cloud over, and we will have another storm this coming weekend.  Hopefully the next storm will not be as strong as last week's, in which we received about 4 inches of rain in 3 days!

    And that leads to another update -- on Lake Cachuma!   As of Monday, the lake had risen 34 feet from it's level measured on 2/16 (in 4 days!)  It  measured 41% of capacity as of Monday, compared to 8% ini September and October!  Unless w have another similar storm, they are projecting that by the end of the rainy seasoon the lake could be at 50% of capacity.   What a difference a day makes!

  • Water, Water, Everywhere

    No photos this time -- but some comments about Oroville.  Oroville is a small (16,000 people) farming community on the Feather River, about 100 miles north of Sacramento, CA.  About 50 years ago, an earthen dam was built on the Feather River, across the street from downtown Oroville.  At 795 feet, this is the tallest dam in the country.  This dam is the source of about 1/3 of the water used in Southern California.  Next to the dam there are two spillways, which allow for the release of water if the dam fills and to keep water from simply spilling over the top of the dam.  The main spillway is concrete lined -- a chute down which water rushes when the dam is full and the gates are open.  The second, commonly known as the emergency spillway, is simply a gate for water to flow out to raw hillside.  Downstream from Oroville, there are major agricultural cities (Yuba City and Marysville) and many smaller ones.  The Feather River feeds into the Sacramento River, which then merges with the American River just outside of Sacramento, and the combined rivers flow to San Francisco Bay.   The lake, which three months ago was the most widely publicized example of a low lake level (the one with the houseboats), is now full and over the weekend they opened the spillway gates on the main spillway.

    Northern California has received a great deal of rain and snow this winter, and there is more to come this weekend -- not enough to break the state's drought going forward, but more than one year's average rainfall.  They are calling the rainfall part of an "atmospheric river."  On the radar, it looks like water flowing from a hose from south of Hawaii towards California.

    Over the weekend, the lake was full, and the gates were opened to the main spillway to allow some of the water to flow down to the Feather River and to make room for more water running off from previous storms and from the current storm and snowmelt in a month or two.  Very quickly, workers noticed a sinkhole developing under the concrete lining -- this sinkhole has now grown to the size of a football field.  So that they could inspect the hole, they opened the gates to the emergency spillway for the first time in the history of the dam.  This allowed water simply to flow downhill to the river, taking with it whatever was in the way (trees, mud, rocks, etc.  Very quickly they saw erosion developing that threatened the integrity of the emergency spillway gates.  With both spillways in trouble, there was a serious threat of major flooding, and 180,000 people were ordered to leave immediately.

    The emergency gates were closed, and the main spillway flow increased.  They are working on a fix for the emergency spillway, dumping 1000 truckloads of boulders every 24 hours into the eroded hole, along with slurry to anchor the rocks and create a smooth surface for the water to flow over.  As of this evening, the risk is reduced sufficiently that the evacuees are being allowed to go home, but with warnings that they may need to evacuate again as conditions change -- weather conditions, dam and spillway integrity, snow melt, river flow, and so on.

    Some 20 years ago I lived in Sacramento -- I think that if I lived anywhere downstream from the Oroville Dam, I would go home and pack all my valuables to be ready to leave again.  If the dam or any spillway should break, they are saying that it would send a 30-foot wall of water downstream -- that could reach all the way to Sacramento, and the rivers are already in flood-control condition through Sacramento.  Furthering the dangers, there is Folsom Dam, on the American River, which merges into the Sacramento just outside of town and which is already full.  There is an extensive area which is used for free overflow of the two rivers -- the Yolo Causeway.  When the rivers are high, the gates to the Yolo Causeway are opened and the water flows freely over agricultural land, and down to the San Francisco Bay, about 100 miles away..  Much of Sacramento is below the level of the levees that protect it -- in a worst case scenario, Sacramento could be lost to a break of the Oroville Dam!

    All of this is happening about 600 miles north of where I live -- although I am not directly affected by any of it, a break would affect the availability of water in Southern California.  Another 1/3 of the water used in the Los Angeles area comes from Lake Mead -- that lake is precariously low due to the drought, and we are likely to see the allocation reduced in the near future.  Los Angeles has massive water storage capacity, and has been filling the tanks with this winter's rainfall.  Santa Barbara's Lake Cachuma lies in a rain shadow, and has currently reached only about 20% of capacity.  Should Oroville Dam or its spillways have further problems of catastrophic proportions, it would create major problems here in "the Southland."

    As Samuel Taylor Coleridge said in his famous poem,

    Water, water, everywhere, Nor any drop to drink.