Hydrology of Forest Decline in Relation to Air Pollution

1990

S. 283-294

3 Abb., 10 Lit. Ang.

Unselbständiges Werk

200085627

The changes of streamflow characteristics influenced by air pollution effects on spruce forests in the upland humid temperate areas of CSFR are analysed here. The small watershed approach was used to determine a hydrological impact, quantity and quality, and compared with the results of standard network and historical investigations. According to an intensive development of herbaceous vegetatin with the forest decline, only a water yield increase in range of 5 percent was observed. From the investigation of historical events the summer rainstorms are considered to be a predominant origin of the catastrophic floods have been registered there in the past. On the experimental basin the summer peakflows not exceeded a periodicity of one year, an increase in range of 8-10 percent influenced by the forest logging was estimated. More important pointed out the snowmelt floods during the end of spring there. A decrease of low flow of 355 days-duration about 18 percent has been observed. The annual total deposition of nutrients on an open field of the investigated uplands was about 40 tons per sq. km during the last ten years. A deposition increase of 30-40 percent was observed under the canopy of experimental forest. Both precipitation and streamwater there are almost always acid with pH bellow 5. A permanent overexceeding of limits given by the Drinking Water Standard was evident in the treated water of the investigated adjacent waterwork for the indicators: pH, maximum contents of ammonium, aluminium, manganese and humin acid, and minimum sum of contents of calcium and magnesium.