Drought of 1975-1976
Central and Northern Europe
Drought Event Summary
The 1975-1976 event was brought about by a relatively dry, mild winter with below average precipitation. This precipitation deficit developed during spring and summer over Western Europe centering in NW France to SE England. Only the Mediterranean and the north-west (Norway) were unaffected. Throughout May and June, the drought spread north and eastward resulting in a strongly contiguous cluster centred over Central Europe that peaked on July 1st, when also a high consistency is seen among the models, suggesting a strong influence of the common forcing and a reliable result. This is confirmed by Zaidman et al (2001) who found the maximum extent for daily streamflow drought to occur on 7 July.
Abnormally hot, dry conditions continued until cold air was advected over Scandinavia in August, breaking the pattern and forming a large, pressure area over the Continent.
Approx. duration: 11/1975-2/1977
Date of SPI-6 min: 7/27/1976
Date of hydrological min: 7/1/1976
Affected regions: Central and Northern Europe
A precipitation deficit was already evident in the late fall and winter of 1975 for Scandinavia and eastern Europe. As spring progressed, this area of drought expanded to include more of central Europe. By the climatological drought peak in late July, nearly all areas of Europe except for the Mediterranean and coastal Norway were experienced markedly below average rainfall. Conditions returned to normal for much of Europe in late fall and early winter of 1976.
Progression of climatological (SPI-6) drought. Climatological drought is defined by the SPI-6, which sums precipitation over the previous 6 months and transforms this value to the standard normal distribution. Negative SPI values (shown in red) represent dry conditions, measured in standard deviations from typical conditions. Percent area in drought is calculated by summing all cells less than the 20th percentile (SPI < -0.84).
The hydrological drought peak occurred on July(7) 1, 1976 and covered the majority of temperate Europe, extending from the UK and France in the west to Russia in the east. The Mediterranean region was largely unaffected.
Peak hydrological drought. with Hydrological drought is based on output nine large-scale hydrological models. Viewed spatially (left), areas with runoff below the 10th and 20th percentiles are shown in red and orange, respectively. The cluster centre (right) shows the centroid from each of the hydrological models during the drought peak.
In parts of Northwestern Europe already the growing season (May to September) of 1975 was characterized by markedly below average rainfall. By June 1975 hosepipe bans had been imposed throughout South West England and were extended to substantial parts of England and Wales during the following months (Rodda & Marsh, 2011). Newspapers also reported on record number of forest, heath and field fires in Denmark and adjacent Northern Germany as well as shortage of fodder in Eastern parts of Norway leading to slaughtering of cattle and transports of milk from the West.
Then, the drought conditions in 1976 combined with a heat wave in June/July particularly hit France and the UK but resulted in widespread socio-economic and environmental impacts throughout Western Europe. Agriculture was extensively affected. Due to insufficient grazing availability and low hay and fodder crop yields livestock and especially dairy farming severely suffered from feed shortages during the hot weather period. This caused early slaughter of livestock at “unprecedented rates” (EIR, 1976). Particularly France, Great Britain and Denmark (all of them having faced drought conditions since 1975) reported drastically fallen milk production. In parts of Great Britain and the Netherlands saline intrusions contributed to agricultural damage (Rodda & Marsh, 2011; Massarutto et al., 2013). Households were impacted through sharply increased prices especially for potatoes and fresh vegetables together with the loss of their own garden produce (Courvoisier et al. 1977; Dornkamp et al. 1980; Rodda & Marsh, 2011).
Location of drought impact reports. Darker colors refer to more reported impacts in the EDII. Scroll over each country to see more detail.
The impact on public water supply services varied spatially. In England and Wales the seriousness of the water supply situation due to prolonged drought was a major problem; despite diverse mitigation measures for a period from beginning of August daily shutoffs had to be applied which finally affected over one million consumers (Rodda & Marsh, 2011; Dornkamp et al., 980). In France limitations in water supply affected urban and rural areas in particular in the East, in Brittany and in touristic areas at the West coast yet were less severe than expected at the beginning of the summer (Brochet, 1977). While the need for a reduction in demand, including sometimes also outdoor water use restrictions (hosepipe bans), was given also in large parts of the Rhine basin, critical regional water shortages and failures of supply remained limited mainly to rural areas where in some cases emergency supply had to be realized by trucks and even helicopters (Gerhard et al. 1983).
Because of low stream flows reduced hydropower production and impaired production of thermal and nuclear power plants were common problems for the energy sector. Further, inland navigation on the Rhine and other important transport routes was heavily impaired sometimes until into 1977 (van der Heijde, 1978; Gerhard et al. 1983; RIZA, 2005). According to RIZA (2005) 1976 belongs to the top five years of largest economic loss for the navigation sector in the Netherlands (ranked fifth after the years 1921, 1949, 1949 and 1959). Across much of Southern and Eastern England land subsidence was experienced on a scale not previously recorded leading to substantial property damage (Dornkamp et al., 1980).
Among the reported environmental impacts of the drought and heat wave in 1976 are impacts on freshwater ecosystems, i.e. the temporary deterioration of (surface) water quality (mainly eutrophication phenomena), algal blooms, extreme water temperatures, depletion of dissolved oxygen to critical levels, massive proportions of sewage effluent, saline incursions, fish kill events (sometimes related to excessive withdrawals for agricultural irrigation), drying up of stream sections with effects on aquatic species and especially migratory fish (Dornkamp et al. 19890; Gerhard et al., 1983; Rodda & Marsh, 2011). In the Dutch delta area an outbreak of avian botulism (over 60 000 cadavers counted) was attributed to the prevailing low water levels, water quality problems combined with the high temperatures during summer (Gerhard et al., 1983). The considerable fall of groundwater levels had a particular impact on oligotrophic wetland habitats in the Netherlands (van der Heijde, 1978; Sykora, 1979). Noted (detrimental) effects of the drought on sites of nature conservation interest in Britain were documented by Hearn & Gilbert (1977 in Dornkamp et al., 1980). Devastating wildfires were widespread in the summer of 1976, again Southern England (up to 40 fold number of fires than in 1974, Dornkamp et al., 1980) and regions in Northern France (three fold area burnt compared to a reference year, Brochet et al., 1977) were severely affected. Besides direct fire damage, European woodlands and forests suffered from the prolonged drought stress and increased incidence of diseases such as the Dutch elm disease, in particular increased dieback of beech and birch was observed (Courvoisier et al., 1977, van der Heijde 1977, Dornkamp et al. 1980; Gibbs & Greig, 1977).
Impact Detail Table
|Drought Event||Country||Start Date||End Date||Impact||Impact Category||Impact Description||NUTS 1||NUTS 2||NUTS 3||Reference|
|1975-76 Europe||United Kingdom||3/1975||1976||7.4||Limitations in water supply to households in rural areas (supply cuts, need to ensure water supply by emergency actions)||Water supplies decreased rapidly till March 1976 due to the drought beginning in 1975, meaning a threat for regional water availability. Some emergency measures had to be implemented, overall only occasional failure of supply occurred||South East;||Hampshire and Isle of Wight;||Isle of Wight;|