Damages From 2014 Flooding
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Damages From 2014 Flooding
The City of Prior Lake and Prior Lake-Spring Lake Watershed District (PLSLWD) staff continually monitor local conditions including winter snowpack, precipitation, and lake levels to assess flooding risk. Early spring is one time of year when flooding potential receives some extra attention. According to the National Weather Service office in Chanhassen, the weather outlook and the potential for snow or rain are the biggest wild card every year. At this point, additional rainfall would be the main spring flood driver.
Based on an analysis done by City staff, there isn’t a strong correlation between the lake level at ice-out and the eventual high-water elevation for Prior Lake in any given year. For example, in 2014 the early spring level for Prior Lake was very close to the long-term average of about 901.6 on April 20; the record flooding level of 906.17 recorded on June 30 was caused by above-average rainfall events over a period of a few weeks in May and June. Other years, such as 2001, start out with high lake levels (902.75 on 4/15/2001) but the lake’s high-water level for the year is recorded shortly thereafter (904.33 on 4/30/2001); in that case melting snow likely contributed to the high-water levels.
CURRENT CONDITIONS AS OF MAY 2, 2018: Ice-out occurred this week and there is no longer any snowpack in the watershed above Spring Lake and Prior Lake. Spring Lake levels have been declining for about a week, although it continues to discharge to Prior Lake. Prior Lake appears to have View Full Article →
View Full Article Prior Lake, Spring Lake, flooding, lake levels, springThe City of Prior Lake and Prior Lake-Spring Lake Watershed District (PLSLWD) staff continually monitor local conditions including winter snowpack, precipitation, and lake levels to assess flooding risk. Early spring is one time of year when flooding potential receives some extra attention. According to the National Weather Service office in Chanhassen, the weather outlook and the potential for snow or rain are the biggest wild card every year. At this point, additional rainfall would be the main spring flood driver.
Based on an analysis done by City staff, there isn’t a strong correlation between the lake level at ice-out and the eventual high-water elevation for Prior Lake in any given year. For example, in 2014 the early spring level for Prior Lake was very close to the long-term average of about 901.6 on April 20; the record flooding level of 906.17 recorded on June 30 was caused by above-average rainfall events over a period of a few weeks in May and June. Other years, such as 2001, start out with high lake levels (902.75 on 4/15/2001) but the lake’s high-water level for the year is recorded shortly thereafter (904.33 on 4/30/2001); in that case melting snow likely contributed to the high-water levels.
CURRENT CONDITIONS AS OF APRIL 23, 2018: There is currently very little snowpack in the watershed above Spring Lake and Prior Lake after the warm weather this past weekend. Lake levels are rising and will continue to rise as the last of the snow melts. The water level of Prior Lake was 902.89 on April 23 which is slightly above the long-term early spring average of about 902.6. The lake continues to discharge through View Full Article →
View Full Article Prior Lake, Spring Lake, flooding, lake levels, springHurricane Harvey just dropped unprecedented amounts of rain in Texas. The huge amount of rain dropped by Harvey was partially a result of the effects of climate change. Human produced emissions of greenhouse gases (like carbon dioxide and methane) have caused a small but significant rise in global temperatures. This, in turn, resulted in warmer than normal water temperatures in the Gulf of Mexico which fueled Harvey, feeding the storm more energy and precipitation and brought greater devastation to Houston.
But- this isn’t just a Houston problem. Here in Minnesota, we are also experiencing increasing frequency and intensity of rainstorms (Source: MPCA). We should take this opportunity to look at how prepared our own local communities are. Are we building our communities to be resilient to climate change ? If not, we’d better get started. We have a choice to make, so let’s choose success.
Excerpts from: http://www.politico.com/magazine/story/2017/08/28/climate-change-hurricane-harvey-215547
In all of U.S. history, there’s never been a storm like Hurricane Harvey. That fact is increasingly clear, even though the rains are still falling and the water levels in Houston are still rising.
Harvey is the third 500-year flood to hit the Houston area in the past three years, but Harvey is in a class by itself. By the time the storm leaves the region on Wednesday, an estimated 40 to 60 inches of rain will have fallen on parts of Houston. So much rain has fallen already that the National Weather Service had to add additional colors to its maps to account for the extreme totals.
But there’s an uncomfortable point that, so far, everyone is skating around: We knew this would happen, decades ago. We knew this would happen, and we didn’t care. Now is the time to say it as loudly as possible: Harvey is what climate change looks like. More specifically, Harvey is what climate change looks like in a world that has decided, over and over, that it doesn’t want to take climate change seriously.
Houston has been sprawling out into the swamp for decades, largely unplanned and unzoned. Now, all that pavement has transformed the bayous into surging torrents and shunted Harvey’s floodwaters toward homes and businesses.
While Harvey’s rains are unique in U.S. history, heavy rainstorms are increasing in frequency and intensity worldwide. One recent study showed that by mid-century, up to 450 million people worldwide will be exposed to a doubling of flood frequency. This isn’t just a Houston problem. This is happening all over.
A warmer atmosphere enhances evaporation rates and increases the carrying capacity of rainstorms. Harvey drew its energy from a warmer-than-usual Gulf of Mexico.
Weather patterns are also getting “stuck” more often, boosting the chances that a storm like Harvey would stall out.
To be sure, a storm like Harvey might have been possible in the absence of climate change, but there are many factors at play that almost assuredly made it more likely.
If we don’t talk about the climate context of Harvey, we won’t be able to prevent future disasters and get to work on that better future.
The symbolism of the worst flooding disaster in U.S. history hitting the sprawled-out capital city of America’s oil industry is likely not lost on many. Institutionalized climate denial in our political system and climate denial by inaction by the rest of us have real consequences. They look like Houston.
The rebuilding process provides an opportunity to chart a new path. The choice isn’t between left and right, or denier and believer. The choice is between success and failure.
View Full Article climate change, extreme weather, flooding, flooding potential, planning, rain, resiliencyUpdate supplied by the City of Prior Lake.
Although the City of Prior Lake and Prior Lake-Spring Lake Watershed District (PLSLWD) staff continually monitor local conditions such as winter snowpack, precipitation, and lake levels to assess flooding risk, early spring is one time of year when flooding potential receives a lot of attention. City staff performed an analysis last year and showed there isn’t a strong correlation between the lake level at the ice-out date and the eventual high water elevation for Prior Lake for any given year.
In 2014, the early spring level for Prior Lake was very close to the long-term average of about 901.6 on April 20, and the record flooding level of 906.17 recorded on June 30 was caused by above average rainfall events over a period of a few weeks in May and June. Other years, such as 2001, start out high (902.75 on 4/15/2001) and the high level for the year is recorded shortly thereafter (904.33 on 4/30/2001); in this case melting snow could have contributed to the high-water levels.
There is currently no snowpack in the watershed above Spring Lake and Prior Lake. Water levels for Prior Lake are above the long-term early spring average of 902.58 as of March 27 and the lake has been discharging through the Prior Lake Outlet Channel since last fall. Our region has been experiencing some very wet weather lately, leading to full storage areas upstream (ponds, wetlands, depressions) and therefore lots of runoff every time we get more precipitation.
Our average annual precipitation is about 31.1 inches and the 365-day precipitation sum (amount of water we’ve received since March 22, 2016) is 40.8 inches. Even with the lack of snow, we could still experience spring flooding, but lake levels will depend only on the precipitation we receive. The National Weather Service in Chanhassen, in their initial Spring 2017 Flood Outlook, agrees with this assessment, stating: “The main flood threat will be determined by the occurrence (or lack of) heavy snow events in March and/or heavy rain events in March and April.” We will continue to keep an eye on the situation.
City staff is currently working on finalizing a plan that includes flood trigger points (lake elevations) for flood response actions and the role the city will play in those actions. The plan will be presented to the City Council soon in the form of a City Policy.
The PLSLWD is also working on short-term flood solutions by looking at how to optimize the operation of the Prior Lake Outlet Structure, which also will involve action at certain lake elevations. Per the recently-completed joint Flood Study, these short-term flood solutions are needed, combined with a long-term strategy of upstream water storage, to help reduce flood impacts on our residents and businesses.
View Full Article Prior Lake, Spring Lake, flooding, flooding potential, lake levels