Mistaeks I Hav Made: Laws of Software Development

http://natpryce.com/articles/000749.html

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Low flow in the upper Elbe River

Foto: Stefan Hässler.

River Elbe in Dresden. Foto: Stefan Hässler (reposted from source). Actual discharge (16 July 2015) ~70 90 m³/s.

I never thought I will ever cross-post news from the yellow press leaders of BILD. Well, never say never, here it is (even covering a hydrological issue!): Trocknet die Elbe aus? (will River Elbe run dry?)

Despite BILD claims that the situation is ‘historic’, water levels and – what is hydrologically more meaningful – discharges have been lower/worse regarding historic time scales (e.g., in summer/fall 1904, summer 1911, winter 1954 or summer/fall 2003).

Here is a brief comparison of some low flows (not a complete list of extreme values!) for the Elbe gauge at Dresden (mean annual low flow is 111 m³/s):

1904   ~60 m³/s
1911   ~55 m³/s
1954   ~25 m³/s
2003   ~100 m³/s*
2015   ~70 90 m³/s**

*The 2002 flood quite well filled the reservoirs in the upper Elbe catchment so that there was enough water for low flow mititgation by controlled release in the very dry summer of 2003.
**On July 16.

However, it is quite likely that water availability and therefore river flow will futher decrease during summer and the first decades of fall. Thus, there is a (yet not exactly specifiable) probability of a worsening low-flow situation on the mid and long run.

Edit (as per 12 August 2015) – keeping track of the further devlopment of the current low flow period:

16 Jul. 2015   ~70 90 m³/s
25 Jul. 2015   ~65 85 m³/s
07 Aug. 2015  ~65 85 m³/s
10 Aug. 2015  ~60 80 m³/s
12 Aug. 2015  ~78 m³/s

N.B.: Intitially given figures for low flow discharges had to be altered in the meantime due to operational flow measurements carried out by WSV required an adaption of the gauge’s rating curve.