{"id":2633,"date":"2014-04-09T12:01:48","date_gmt":"2014-04-09T12:01:48","guid":{"rendered":"http:\/\/www.ericjorden.com\/blog\/?p=2633"},"modified":"2014-05-09T21:33:46","modified_gmt":"2014-05-09T21:33:46","slug":"image-credits-and-why-forensic-engineers-like-wet-weather-the-heavier-the-rain-the-better","status":"publish","type":"post","link":"http:\/\/www.ericjorden.com\/blog\/2014\/04\/09\/image-credits-and-why-forensic-engineers-like-wet-weather-the-heavier-the-rain-the-better\/","title":{"rendered":"Image credits, and why forensic engineers like wet weather, the heavier the rain the better"},"content":{"rendered":"

The tranquil sea coast in the heading is deceptive.<\/strong><\/p>\n

Many forensic engineering problems are caused by water or water is\u00a0a factor in the problem.\u00a0 And – at the risk of annoying you, I must tell you that experienced forensic engineers\u00a0like heavy rain when investigating a flooding or drainage problem.<\/p>\n

They’ll\u00a0also use\u00a0somewhat unconventional methods to gather data\u00a0to solve the problem – this blog site is partly about forensic methods.\u00a0 And think outside the box when analysing the data.<\/p>\n

There’s no shortage of\u00a0flooding and drainage\u00a0problems in eastern Canada\u00a0in the\u00a0spring.<\/p>\n

We are almost always\u00a0interested in how rain and melt water are flowing across a site and around, beneath, and into\u00a0structures.\u00a0 We can do detailed topographic and contour surveys –\u00a0which can take days, and determine\u00a0drainage patterns and watercourses\u00a0the text-book\u00a0way.<\/p>\n

Or we\u00a0can wait and hope for heavy rain\u00a0– sorry, and note and measure the location of the water as it flows across the site and\u00a0in the vicinity of the\u00a0structures.\u00a0 I often do the latter.\u00a0 It’s very accurate.<\/p>\n

Also, we note\u00a0in some problems where it’s not flowing –\u00a0this was relevant in one problem I investigated a few weeks ago.<\/p>\n

We’re interested in discharge too.\u00a0 I went to one site four times in 24 hours to\u00a0measure\u00a0the discharge\u00a0in a drainage channel – I was interested in how quickly\u00a0the site drained after a rain storm.\u00a0 Quite quickly as turned out.<\/p>\n

Noting where water was not flowing was relevant in another problem I\u00a0looked at a couple of years ago.\u00a0 Unfortunately, I was retained after $140,000\u00a0was spent in misguided\u00a0investigation.\u00a0 Getting out on a rainy day\u00a0and noting where water was not flowing\u00a0would have saved an awful lot\u00a0of money.<\/p>\n

Sadly, sometimes there’s no heavy rain when a drainage problem is being investigated.\u00a0 Or greater flow is needed than can be expected from typical rainfalls for the season.\u00a0 Fire hoses and water trucks can be used to generate flow.\u00a0 I planned this for one investigation.<\/p>\n

The scene in the heading is Prospect Bay, Nova Scotia, Canada,<\/strong> photographed by J. Knoll, Halifax.<\/p>\n

Other days are not\u00a0as nice as this scene along the 1,000s of kilometres of Atlantic sea coast – almost as long as Canada is wide.\u00a0 Nor are the 1,000s of rivers\u00a0and streams that flood \u2013 and they certainly have flooded this late winter, early spring, 2014.<\/p>\n

The rivers and lakes are still flooding this morning after the heavy rain yesterday as the land sheds the rainfall and melt water in runoff to our watercourses.\u00a0 And the lakes are overtopping their banks \u2013 there are more than 4,000 lakes in Nova Scotia.\u00a0 That\u2019s just the water you can see on the ground surface.<\/p>\n

There is also the ground water – the water table, that you can\u2019t see.\u00a0 Water that is just below the ground surface or\u00a0quite deep, and fluctuating up and down all the time \u2013 certain to be well up and high after the rain this year.<\/p>\n

Ground water flows through the ground much like a river flows on the land; welling up behind obstacles buried in the ground \u2013 e.g., foundations and basement walls, like river water wells up behind a boulder in a stream.<\/p>\n

Forensic engineers use monitoring wells to measure how ground water flows and drains beneath a site, and also measure ground water discharge.\u00a0 They are looking for similar parameters to those for surface water.<\/p>\n

It\u2019s been said that if you could take the water out of the ground, out of the soils and rocks beneath our feet, you would reduce foundation and ground engineering problems to a fraction.<\/p>\n

The camera\u00a0operator in the heading<\/strong> is filming the re-enactment of a fatal MVA from a sea king helicopter during a forensic engineering investigation.\u00a0 The sea and snow – frozen water, were factors in the fatal accident.\u00a0 For this forensic investigation, I set up a full scale test site at\u00a0Shearwater airbase\u00a0in eastern Canada complete with:<\/p>\n

    \n
  1. A\u00a0traffic lane,<\/li>\n
  2. An obstacle in\u00a0the lane,<\/li>\n
  3. A\u00a0vehicle,<\/li>\n
  4. Monitoring devices to track vehicle behaviour on striking\u00a0the obstacle, and,<\/li>\n
  5. Film crews to record the tests.<\/li>\n<\/ol>\n

    The surveyor in\u00a0the heading<\/strong> is checking the\u00a0adequacy of the underpinning\u00a0of a structure during\u00a0a forensic investigation.<\/p>\n

    Surveyors also carry out topographic surveys of sites with drainage problems.\u00a0 But, noting and measuring where the water is draining during heavy rain can often give us all the data\u00a0we need and much quicker and more accurately.<\/p>\n","protected":false},"excerpt":{"rendered":"

    The tranquil sea coast in the heading is deceptive. Many forensic engineering problems are caused by water or water is\u00a0a factor in the problem.\u00a0 And – at the risk of annoying you, I must tell you that experienced forensic engineers\u00a0like … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[1],"tags":[],"_links":{"self":[{"href":"http:\/\/www.ericjorden.com\/blog\/wp-json\/wp\/v2\/posts\/2633"}],"collection":[{"href":"http:\/\/www.ericjorden.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.ericjorden.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.ericjorden.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.ericjorden.com\/blog\/wp-json\/wp\/v2\/comments?post=2633"}],"version-history":[{"count":17,"href":"http:\/\/www.ericjorden.com\/blog\/wp-json\/wp\/v2\/posts\/2633\/revisions"}],"predecessor-version":[{"id":2650,"href":"http:\/\/www.ericjorden.com\/blog\/wp-json\/wp\/v2\/posts\/2633\/revisions\/2650"}],"wp:attachment":[{"href":"http:\/\/www.ericjorden.com\/blog\/wp-json\/wp\/v2\/media?parent=2633"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.ericjorden.com\/blog\/wp-json\/wp\/v2\/categories?post=2633"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.ericjorden.com\/blog\/wp-json\/wp\/v2\/tags?post=2633"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}