DIGITALNA ARHIVA ŠUMARSKOG LISTA
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ŠUMARSKI LIST 13/2005 str. 16     <-- 16 -->        PDF

Z. Vicha: FIFTY YEARS Ol" THE FORESTRY HYDRO-PFDOLOGICAL RESEARCH WITHIN THE FOREST ... Šumarski list - SLJPLEMENT (2005). 7-16
METOD OF RESEARCH WITHIN THE TWO BASINS


Research within the basins of MR and CE is based
on evaluating of the forest management measures with
respect to the run-off, and water balance. Basic forest
state, orographic and stand conditions, different in the
two basins, are considered.


Total volume felled within the two basins (Tabs. 1,
2) shows, that felling was intensively motivated by the
research aims by the end of seventies. In eighties, after
hard damage by air pollution, mainly in the exposed
slope and ridge part of the basin MR, felling was nearly
stopped. Fast regeneration in CE basin was also closed,
and it was limited only to the most important forestry
measures, in spite of the fact that damage by air
pollution was not that heavy in this basin. However, the
aim of the research was not affected, as the regeneration
was in such a state that the run-off could be affected
by its results in measurable way.


In both experimental basins the precipitation and
run-off characteristics, same as other meteorological
values, are measured by classic methods, newly completed
by digital methods of measuring. Thus the informative
value of the data was improved, mainly for the
extreme hydrological situations. Nevertheless, the
classic methods are still important data source, and
they can be used to complete or correct the data measured
digitally, and they also help in case of the digital
equipment failure.


To measure meteorological values, meteo-stations
have been installed within the basins, controlled daily
by the observers. The stations are equipped by classic
case with normal thermometer, wet thermometer, and
thermometer for measuring of maximum and minimum
temperature. Also the length of sunshine is recorded.


Measuring of precipitation is of importance, done
in more detail than the routine in climatology. In each
basin four totalisers are installed, three of them in water
divide, one in the valley, in centre of the basin. Total
precipitation is measured on monthly base. Precipitations
in time are recorded by pluvial-graphs on weekly
base, giving important data on floods and their analyzing.
The station precipitation meters verify reliability
of measuring. In winter the layer of new snow is measured,
total snow cover and its water value. Monthly
total precipitation of the basins is calculated using the
polygon method by Horton-Thiesson.


Water run-off is measured in the concrete measuring
funnels with limnigraphic manhole (shaft). They
are equipped with limnigraphs OTT of week regime.
Water level on the scale, and water temperature are measured
daily by the observer. Run-off is evaluated on
the base of consumption curves, the values are verified
repeatedly. Minimal flow is measured in 50 litre calibrated
container, under the wire of funnels.


There are three funnels in the CE basin, measuring
independently run-off of the two parts of the basin, and
also run-off down the confluence.
More detailed information on digital measuring:


The 16-channel registration unit M4016, supplied
by accumulator, is the base of the monitoring station
MS 16.


The registration unit makes possible to connect all
types of measuring sensors of standard. All common
sensors with standard, current, frequency or pulse output
can be connected to the unit. A number of ultrasonic
and electrochemical probes with digital output can
thus be connected to the unit, of digital output of data
measured. Communication to the unit is done by the
MOST programmes, and the actualised version of
MOST 32, respective. The programmes transfer the data
to the notebook, state the parameters of data measuring
and storing, and data processing, using table and
graph outputs.


To measure water level in the open funnels, the ultra-
sound probes are used, US 3000. Microprocessor in
it is calculating the distance on the base of the time interval
of the ultra-sound impulse sent and its reflection,
corrected on the base of air temperature. Basic resolution
of the probe is 1 mm.


Air temperature is measured by platinum resistance
thermometer Pt 100 with a flow transferor in the in the
head. To measure absolute air moisture capacity sensor
with flow output is used. Thermometer ans moisture
sensor are protected by radiation cover, and they are
placed in the mast, in a height of 2 m above soil surface.
Water temperature is also measured by platinum
thermometer Pt 100. The whole complex is packed in
silicone, so it can be placed in water.


To measure volume and intensity of precipitation,
meters type SR02 are used, of catching area of 200 cm2.
Precipitation meter is connected to the pulse input of the
registration unit. This registers, in one of the channels,
volume of precipitation, within the time period given by
the set interval of data storing by the unit. Principle of
the use of precipitation meter is based on the mechanism
of dumping boat, divided in two parts, to get the electric
pulses, depending on precipitation intensity. The rain
comes through the opening of strictly given area, directly
to a funnel, and it goes to the upper part of a boat.
Where the upper part is filled by adjustable volume of
precipitation, the boat dumps. This half of the boat is
empted, and the other half gets under the funnel. This
process is on going by the end of rain. Magnet, fixed in
the boat body, in each dumping connects the contact,
placed in the boat stick. This connection, depending on
flow of defined precipitation volume, makes possible to
register number of dumps and so precipitation volume.