{"id":4190,"date":"2015-10-06T10:05:55","date_gmt":"2015-10-06T15:05:55","guid":{"rendered":"http:\/\/admin.patheos.com\/blogs\/jenniferfitz\/?p=4190"},"modified":"2015-10-06T10:26:48","modified_gmt":"2015-10-06T15:26:48","slug":"is-sc-really-having-a-1000-year-flood-i-dont-think-so-scflood","status":"publish","type":"post","link":"https:\/\/www.patheos.com\/blogs\/jenniferfitz\/2015\/10\/is-sc-really-having-a-1000-year-flood-i-dont-think-so-scflood\/","title":{"rendered":"Is SC Really Having a 1000-Year Flood? I don’t think so. #scflood"},"content":{"rendered":"\n<\/head>

Statesmen have a right to poetry in their oratory, and I give Governor Haley every allowance for referring to the flooding in South Carolina as something that happens \u201conce in a thousand years.\u201d \u00a0The point she wishes to make is that the present events were utterly unexpected, and I agree with her. \u00a0There are countless cases\u00a0where you can glance at the land and the forecast and be utterly unsurprised by a bit of flooding; the recent disaster in the Midlands is not one of those events.<\/p>\n

All the same, I\u2019m going to hazard that if we look at some snatches of recent history \u2014 and by \u201crecent\u201d I mean less than a century \u2014 the picture is a bit different.<\/p>\n

How much water does this place get?<\/h2>\n

Seasonal fluctuations in water levels are normal, and so are variations from year to year. Sometimes summers are wet and winters are dry, sometimes it runs the other way around. \u00a0We are used to the rivers and creeks doing their thing, going up and down. \u00a0It entertains. \u00a0In recent memory, however, there has been nothing like the overwhelmingly massive flooding we are seeing now. \u00a0The evidence, unfortunately, is that this is because we are forgetful.<\/p>\n

The Lake Murray Dam<\/a> was completed in 1930, and one of its purposes was flood control. \u00a0If you look at river flow records on the Congaree<\/a>, you\u2019ll notice some very high-water years prior to the building of the dam. \u00a0But note: This year\u2019s record high during the floods at 155,000 cfs was exceeded by a long shot in 1936<\/a>\u00a0at 231,000 cfs. \u00a0Take a look at the data \u2014 there were yet\u00a0other big-flood years since the dam was built.<\/p>\n

For data from this year\u2019s flood, check out the feed at the Congaree Riverkeepers Facebook page<\/a>. \u00a0Side note: The Gervais Street Bridge was completed in 1928<\/a>, which means it\u2019s already survived 300,000+ cfs. \u00a0Don\u2019t fail us now, little bridge!<\/em><\/p>\n

The geography of the city underscores this point. \u00a0In the past twenty years there has a been a flurry of development along the river, as if someone suddenly noticed there was a major scenic area right there in the middle of everything. \u00a0But if you had shown up in 1990, here\u2019s what you would have found on the riverfront: A chicken factory (still there), a couple of water treatment plants (ditto), and a prison. \u00a0The scenic Vista tourist area just up the hill from the river (around the recently-built Columbia Convention center) was all industrial property \u2014\u00a0factories and industrial-supply houses.<\/p>\n

(In 1990 there were two pioneering apartment complexes \u2014 but nothing at all like what you see today.)<\/p>\n

Part of this was due to the river\u2019s history as a transportation pipeline and as a power source for mills. \u00a0Likewise, there\u2019s obvious logic to laying out the state capital farther up on the more buildable flat lands at the top of the hill. \u00a0But if you look at the siting of the mill villages on either side of the river, you\u2019ll notice that all the historic development leaves plenty of elbow room for flooding. \u00a0Not only is the obvious floodplain kept clear, but there\u2019s a bit of extra cushion before you reach the historic structures.<\/p>\n

We who are living in 2015 are surprised by so much rain and what it does to a river or creek. \u00a0Someone building in 1915? \u00a0Either they knew to expect massive floodwaters, or else the evidence of their ignorance has since washed away.<\/p>\n

Just how old is this place, anyway?<\/h2>\n

The City of Columbia has been around for ages, but what we overlook in thinking about the present floods is just how new most of the residential areas are. \u00a0Forest Acres, on the eastern side of the city where the most disastrous flooding is occurring, was only developed into neighborhoods from the 1950\u2019s forward.<\/p>\n

What did 1950\u2019s southern suburbia look like? My great aunt, who bought a brand new home on the other side of the river in the avenues of Cayce (West Columbia), explained how Knox Abbot drive \u2014 one of the major arteries feeding the city \u2014 was then a dirt road. \u00a0Urbanization as we know it is new. \u00a0Very new.<\/p>\n

We think of sixty-five years as being a long time ago, but in terms of weather cycles and flooding probabilities, it simply isn\u2019t. \u00a0Unless you mean your city to be disposable, it has to be built for the weather you can reasonably expect during the lifespan of the homes and neighborhoods you hope to keep.<\/p>\n

What place for dam-protected neighborhoods?<\/h2>\n

The pond-dam system of flood control is what makes large portions of creekside land in central South Carolina arable and habitable. \u00a0Without the dams in Forest Acres, the neighborhoods as we know them could not function \u2014 so they will almost certainly be rebuilt. \u00a0Alongside a wild creek is not a good place to put a tame neighborhood.<\/p>\n

Something to understand before asking petulant questions about why the dams in Forest Acres and farther afield weren\u2019t made to handle more water is that there is much more room for error\u00a0in a rural, undeveloped setting \u2014 which is where most dams were situated, for lack of urbanization, until only very recently in South Carolina history.<\/p>\n

Dirt roads are prone to erosion, which is why asphalt is so popular. \u00a0But when you have a dirt road, you can see the dirt wash away. \u00a0In contrast, the terrifying sudden collapse\u00a0of paved roads<\/a> happens because the dirt below has eroded, and the pavement gives way only when it is no longer supported. \u00a0In other words: Until recently, the roads that got washed out by the odd dam-failure didn\u2019t necessarily do so in a way that took anyone by surprise.<\/p>\n

Likewise, in a rural area there\u2019s more room for absorbing floodwaters. \u00a0Build your home on higher ground, and if the dam goes you\u2019ll lose some crops, but it isn\u2019t, if you do it right, your entire life\u2019s everything. \u00a0The Forest Acres floods have been so catastrophic because pavement serves as a channel and funnel for water, not a sponge.<\/p>\n

How do you build a disaster? Put your history on backwards.<\/h2>\n

We have a disastrous paradox going on in the Midlands:<\/p>\n