Dependable Erection

Wednesday, January 09, 2008

Impressions of the drought forum

First off - Kevin's play-by-play is here. The N&O report by Matt Dees is here. And Ray Gronberg's report in the Herald-Sun is here.

Adding - there's a good analysis of the meeting over at Bull City Blue also.

Two things struck me, and they're kind of hinted at in the various reports, but i wanted to put a magnifying glass on them.

A number of the panelists were clear in stating that Durham and the Piedmont have seen longer periods with less rainfall in the past, and not necessarily going back into prehistory, either. Forum moderator William Chameides remarked, and i'm paraphrasing here, that a natural response to this knowledge is to think that what we're experiencing now is no big deal.

Actually, and maybe this is more an example of my twisted thought processes than anything else, i think just the opposite. If this moderate shortage of rainfall is causing such a serious crisis, then how much worse are things going to be in 8 months if rainfall remains 30% below "normal"? I suspect the answer is "a lot."

The second thing i noticed was a more general disconnect between the "citizens" and the "experts" on the panel. I think this was represented best by Sydney Miller, who attempted to point out that Jordan Lake is a vastly underutilized water storage medium that, if tapped more completely, could help the region meet its water needs for the next several decades. On the other hand, citizens were consistently pushing to have our leaders start taking bolder steps, like requiring developers to install state of the art water conservation fixtures in their new construction, or follow best practices in xeriscaping as well as preserving older growth mature trees rather than clear cutting and replanting with water intensive foliage. Or continuing and enhancing education efforts to get everyone to understand that reducing water consumption is a permanent lifestyle change that needs to happen.

There is, in almost all fields, a tendency on the part of "experts" to listen to the little people, nod their heads sagely, and remind the folk that, after all, they're the ones who study these things and that the rest of us shouldn't worry.

Ummm, no. That's not how it works.

Decision makers need to be listening to all of the rabble on this issue. Quite frankly, that's where the best ideas are going to come from.

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17 Comments:

  • If you want an idea of how bad it could get, read "The Worst Hard Time" by Timothy Egan--- first-person narratives of the dust bowl, its causes and consequences.

    They didn't think it could happen to them, either.

    By Anonymous Anonymous, at 10:02 AM  

  • I happened to see the coverage of NBC 17 which focused almost completely on the "how can we get enough bottled water when we all run out?" issue, which seemed like a tiny part of what you and Kevin have noted. See here: http://www.nbc17.com/midatlantic/ncn/news.apx.-content-articles-NCN-2008-01-08-0026.html

    By Blogger Steve Jones, at 10:43 AM  

  • Regarding Lake Michie, I was recently told that it is particularly vulnerable to area drought because it has very little headwaters flowing into it. In other words, when it rains upland, we get very little of that water then flowing in to Lake Michie because nothing much upland feeds into it.

    Have you heard this before, Barry?

    By Blogger Durham Bull Pen, at 10:45 AM  

  • steve - i think that people can relate to images of huge quantities of bottle water being trucked into a city. We've seen it on TV more than once, and it does resonate.

    But it also requires a bit of meta-analysis of how media works, and how the relative significance of varying events gets flattended out (literally and figuratively) by the glass between us and what we see on TV. That's a different blog post. But i can understand why a TV newscast would choose that segment to focus on.

    DBP - i haven't heard that specifically about Lake Michie. I will point out that during the Christmas period rainfall, inflows at Lake Michie topped out at around 1000 cubic feet per second, or 650 million gallons per day (rounded). According to the USGS, the median for this date is 80 cfs, or 51 million gallons per day. Even this lower number is above the replenishment of around 20 million or so gallons per day of usage. The historic high for this date is almost 2500 cubic feet per second.

    So i suspect with adequate rainfall, inflows into Lake Michie are sufficient. In fact, if we get enough rain over the next several days, i could see Lake Michie easily adding another month of supply (at the 20 million gpd usage rate). So while i'm not saying that the headwaters issue isn't real, i'm not convinced that inadequate inflow is the culprit.

    By Blogger Barry, at 11:00 AM  

  • DBP: I know you weren't asking me, but...

    This is absolutely true, for both of Durham's reservoirs. The Flat River, which feeds Lake Michie, basically starts in the south end of Person County, and only drains a narrow area of northern Durham county below that, basically the basin that Rougemont sits in. Little River (which feeds the reservoir of the same name) drains a similarly narrow valley from northeast Orange County through a narrow band of northeastern Durham County. Jordan Lake, on the other hand, collects just about everything from the southern halves of Orange and Durham county and a big chunk of Chatham.

    To answer Barry more generally, the biggest thing I got from Kevin's wrap-up is confirmation of something I've thought for a while. Even with the drought, we're still a ridiculously wet region, and there are plenty of major cities in the west that would kill to have our 2007 rainfall levels. The problem is we use too much of it and have very minimal infrastructure. Tiered rates would help, of course, but also, in the long run, there's still plenty of water around if we try a little harder. For one thing, there's the comparatively huge Mayo and Hyco lakes in N. Person county, just 20 miles away. And if we somehow managed to overtax those, there's the three Roanoke River reservoirs, each of which dwarfs both Jordan and Falls Lakes. Sure, the furthest of those would be 50 miles away, but hey, the LA aqueduct is well over 200 miles long.

    Our problem isn't low water levels -- it's that we've become accustomed to basically unending cheap water.

    By Blogger Unknown, at 11:15 AM  

  • To follow up (Barry posted while I was typing), the problem isn't the amount of water in the drainage. It's that in a drought, it's a very small target for scattered storms to hit. In November there was a pretty nice rainfall that did absolutely nothing for Durham or Raleigh because it all hit the southern end of the Triangle, completely missing the Durham reservoirs and the Falls Lake watershed.

    By Blogger Unknown, at 11:17 AM  

  • That's probably a pretty good explanation, Michael.

    What it says to me is that we really need to do a better job of managing our water supply (that is, capturing more of our rainfall for long term storage) than we do.

    Oh yeah, and stop watering artificial surface playing fields during a water shortage.

    By Blogger Barry, at 12:14 PM  

  • Lot of misinformation about watershed sizes in this thread.

    Michie's watershed is bigger than Little River's, 170 sq miles vs. 105 sq miles. Neither is huge compared to Falls or Jordan lakes, but Durham's customer base is a lot smaller than Raleigh's.

    Jordan drains 1,690 square miles -- a good bit of the upper Piedmont. Remember that its main feed is the Haw River. So it drains a lot more than Orange, Durham and Chatham counties.

    Michael is right that where rain falls matters. Discounting Jordan for a second, rain that falls outside the Michie and Little River watershed(s) might as well be falling in California for all the good it does us.

    I haven't done enough work yet to write a story, but after playing with calculus and my computer a little over the weekend it appears to me the streamflow occurring the first 24 hours after the rain stopped before New Year's potentially added enough water to Lake Michie to add 14 days' worth of water to the city's stocks at present consumption rates. I haven't run the numbers for Little River yet nor am I able to go much beyond the first day of runoff because of the limitations of the software I'm using (Mathematica 2.2). But it's clear we got a big rain -- and that that sort of daylong deluge is just what we need.

    I didn't opt to write about trucking bottled water because the point seemed a little nonsensical to me. The logistic system we have, truck and rail based, already handles our food, manufacturing supplies etc. Given that we can expect a lowering of economic activity in the city if we ever get to the point of rationing, it seems to me that there's be plenty of slack in the system to handle water deliveries.

    By Anonymous Anonymous, at 12:57 PM  

  • Ray - i don't know that we need to get into that kind of sophisticated math to ballpark what we received from the new year rains.

    According to the USGS sight, there wera about 48 hours where inflows at Lake Michie exceeded 100 cfs (750 gallons per second). Of that, about 24 hours exceeded 200 cfs (1500 gallons per second) and 12 hours above 500 cfs (3750 gallons per second). Flow peaked right around 900 cfs (6750 gallons per second.) We can leave that peak flow out of our calculations for now.

    Simple multiplication/addition gives us a minimum of 291.6 million gallons of inflow during that 48 hour period, or about 15 days at 20 million gallons per day. These caluclations understate the inflow by between 10 and 15%.

    Now, are there other locations that also received rain that could be stored and used? Absolutely. but whether or not those locations are available for use by areas that might not have gotten similar inflows is a political decision that our regional and state leaders are going to have to make. From my perspective, the citizenry is far ahead of the leadership in seeing this.

    By Blogger Barry, at 1:25 PM  

  • Barry, we're both integrating a function, we're just going about it a little differently. :-)

    One thing to bear in mind: Streamflow actually doesn't equal supply on a 1-to-1 basis. There will be losses from evaporation, ground absorption etc. Those I suspect would be small but still something engineers have to reckon with.

    By Anonymous Anonymous, at 1:37 PM  

  • i had a brief, shiny moment back in 1982 when that calculus stuff suddenly clicked in my head and made sense.

    then i got married and had kids and lost it all.

    maybe it'll rain tomorrow.

    By Blogger Barry, at 1:46 PM  

  • I would just suggest that there is error on the upside, too, there may be significant inflow of groundwater that may explain why reservoir levels have remained constant or increased despite low levels of inflow the past few days.

    By Anonymous Anonymous, at 2:47 PM  

  • Ray: I'd forgotten that the Haw actually drained into Jordan Lake -- I was thinking Jordan lived mainly off of the upper creeks, then drained into the Haw.

    But calling 105 vs 170 "similarly narrow" hardly qualifies as misinformation, I think.

    By Blogger Unknown, at 2:50 PM  

  • Oh, one more thing. Ray, be careful with your hydrological predictions -- that's a messy business. If you're preparing this for a story, you might want to call Larry Band or Martin Doyle at the Geography Dept. at UNC. They do that kind of thing for a living. (Particularly Larry)

    By Blogger Unknown, at 2:52 PM  

  • Durham is near the head of the Neuse River watershed.

    Upper Neuse River watershed

    This includes the Eno and other rivers and illustrates the points made above.

    There's not that much land area to collect water for Durm. So even when it rains, not much water is captured.

    By Anonymous Anonymous, at 6:53 AM  

  • Not to be picky, but the additional link at the top of this post isn't to BlueNC but rather to Bull City Blue. That blog is up and running again after a post-municipal-election hiatus.

    By Anonymous Anonymous, at 11:19 AM  

  • That's what happens when i post before my morning cup of tea.

    By Blogger Barry, at 11:24 AM  

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