Information on the Dnepr reservoir and Desna river monitoring
Program designed for and realized by the State Main Ecological Inspectorate in Kiev in 1999.
part 1: overview / aim
river Dnepr and its tributary Desna are the main drinking water sources
for Ukraine and its capital Kiev. In Ukraine, about 70 % of raw water
are withdrawn directly from these two rivers. Six huge reservoirs have been build to gain electricity (amongst other reasons) from the Ukrainian part of the Dnepr. The Kiev Reservoir (see photo) is situated north of Kiev in the North of Ukraine. It is mostly shallow (about 4 - 8 m deep), but about 90 km long. Its sediment is still contaminated with radionuclides. Wind stress can lead to a re-suspension of sediment and endanger the preparation of save drinking water
in the main water work a kilometer downstream.
Another big problem for the water work is eutrophication in the reservoir. High
concentration of phytoplankton (algae and cyanobacteria) in the raw
water, as observed in the Dnepr and in the Desna river, leads to a severe contamination
of drinking water after the 1st chlorination. The development of
phytoplankton in the Dnepr, and the occurrence of chlororganic
compounds in the drinking water should therefore attentively be
observed. The water works of other big cities are located downstream along the river. Water quality however, is not always sufficient and can cause severe problems. Chlororganic compounds
in concentrations up to 160 ug/L have often been detected in the Dnepr
and its tributaries. To better understand these problems, a special
ecological monitoring program has been started in early 1999. The
investigation was carried out by the laboratory of the Main State
Ecological Inspectorate, Kiev (MEP). It includes:
of substances, which have led to high turbidity and problems in the
water work during the winter 98/99. (For some time, the use of Dnepr
water was impossible.)
- study of occurrence, causes and behavior of dissolved organic substances and phytoplankton. (Both lead to the formation of chlororganic compounds after disinfection of raw and drinking water.)
of the Dnepr water quality including the Kiev reservoir, are also
performed by some other laboratories. The here described program was
designed to give supplemental information, which, in this form,
is not available elsewhere. Therefore special ecological
investigation methods have been used which - as far as known - are not
part of other programs.
(Analytical information sources are given in an overview of methods). Following, only no-routine methods (which are less used in Ukraine) will be mentioned:
dynamic of phytoplankton development has been followed by measuring not
only chlorophyll a (as an indicator for phytoplankton-biomass) but also
the potential photosynthetic activity. This activity can be determined
by measurements of the Oxygen Production under standard Laboratory conditions (OPL; Russian letters PKL = ПКЛ). The method follows the German norm (DIN 38412-L 14). The "laboratory conditions" are:
20 oC, 24 hours incubation time, ~1300 lux.
For Russian readers, a short description of the ПКЛ method (OPL) is available here. A figure, showing the relation between OPL and chlorophyll a, one can find here. The proportion OPL/chlorophyll gives the "photosynthetic capacity".
matter has been measured using the UV absorption at 254 nm
(SAC254) and the chemical oxygen demand (COD). The UV absorption is
very sensitive to humic acids. Calculating the proportion between
SAC254 and COD will therefore give an idea on the nature of the organic
matter. (more details)
in the middle of the reservoir and from different depths was not
possible for technical reasons, but 5 different places along the
western and eastern shores and downstream of the reservoir could be
visited twice a month until July '99, later about once per month.
ice cover of the reservoir, atmospheric aeration is completely reduced
and oxygen content can drop to almost near zero and cause fish kills as
in March 1999. The resolution of many compounds from the sediment is
much stronger than before, especially manganese (Mn) concentration is increased in the water.
substances consist, first of all, in humic matter and phytoplankton.
After the thawing of ice, phytoplankton development immediately
started and reached maximum values already on the 7th of April '99. If
weather gets worse (cloudy) for about a week or more, the phytoplankton
density is strongly diminished to near zero. Other factors influencing
the phytoplankton, as for example phosphorous and zooplankton, have still to be investigated.
long as the phytoplankton density is high, it differs very much
between the five places. This is obviously the effect of wind
stress and/or nutrients. As an indicator for photosynthetic active
phytoplankton, the results of OPL measurements are presented
graphically. Especially Cyanobacteria were accumulated near the banks
but Cyanobacteria water blooms over nearly the whole surface of the
reservoir, as in earlier years, have not been observed in the years
1999 and 2000. From November till March, the reservoir is almost
completely covered by ice and sometimes snow
(no transparency!), and the water level falls more than 1 m.
Surprisingly, the phytoplankton (mostly diatoms) reached again very
high concentration in December 1999 under the new ice cover.
The maximal oxygen content under the ice cover - 100 m away from the
shore - was 21 (twenty one) mg/L! The influence of phytoplankton on the
oxygen concentration (near the surface) is shown . Downstream of the
reservoir, water surface was still open 1st of December. The Desna
river was additionally investigated for comparison. Its water was
turbid over a longer period of time because of bank erosion and
transport of silt or clay. Phytoplankton
also developed, but mostly to a smaller extend than in the Dnepr. Only
in October 1999 and September 2000 a much higher content was registered
(compare figure below). Another group of
compounds leading to the formation of chlororganic substances in the
water work are humic acids. Together with iron and manganese, they give
the Dnepr water a brownish color all over the year. Therefore it is
important to get an idea about the origin and composition of the organic compounds on a regular basis. Afterwards it should be possible to make a prognosis on the formation of chlororganic substances (measured as AOX
or THM). Figures for prognostic calculations of THM formation have
already been published ten years ago. Humic acids, their ecological
importance and their behavior in the water works are subject of further studies. A few aspects including analytical information and further results are reported here.
The diagrams show, as an example,
the development of phytoplankton (its photosynthetic activity) from
March 1999 to September 2000 in the Dnepr (5 sampling points, 1st graphic ) and in its tributary, the Desna river (columns in figure below). The photos show the Desna in summer and winter.
Due to a lack of precipitation (snow and rain) in winter and spring 2015, the floodplains of r. Desna were not flooded. The water level in the Desna was already very low and reached a minimum in summer and autumn 2015. Parts of the river bed near the shore, which were not visible during the past 20 years or more, were dry (photo below).
The diagram shows the average monthly discharge of the r. Desna at Chernigov (150 km north of Kiev).
OPL, the figure below shows curves of water temperature (blue) and pH
values (red) as well for the Desna river. As expected, OPL and pH are
correlated (r = 0,65; p < 0,05). The presentation of monitoring
results was interrupted end of the year 2000 because of technical
reasons in the lab (s.fig.below).
below presented figures show the ecological relevance of phytoplankton
for other parameters. Its photosynthetic activity influences the
oxygen content below the water surface (r = 0,83; p<0,05). Its
biomass seems to be an important factor for the biochemical oxygen
demand, measured as BOD5 (below).
basic organic load in the Dnepr water is built by humic matter. Its
concentration changes in dependence of the origin of water: in the
north-west of the catchment area, swamps are accumulated. They
permanently spend their water into the tributary Pripjat and its tributaries. Water from the North-East
contains less humic acid but more nutrients. More explanations and
information for the analytical description of different water types
have been prepared for presentation.
reasons for the deterioration of raw water quality are substances
resolved from the reservoirs sediment in winter and phytoplankton
development in summer and winter. Humic substances, mainly originating
from the Pripjat swamps, can cause problems in the water treatment plant all over the year.
The Desna river water is often very turbid (silt/clay) because of bank erosion. This slightly diminishes the phytoplankton content compared to the Dnepr.
Other Information sources
A more complete overview with respect to environmental impacts of the
whole Dnepr river basin, is given in the following link:
3. A few statistical data and thematical river basin maps have been published in the www by the World RESOURCES INSTITUTE.
4. EPR Recommendations made to Ukraine by the UN/ECE Committee on Environmental Policy
see chapter 8: water management
5. Further information can be found in the World Bank report no. 12238-UA from 1993.
A new, excellent but only quite short overview over the actual state of
other big rivers in the world is given in a press release available
through the WWC homepage.
7. Ecological monitoring of the Dnipro reservoir north of Kiev with the focus on drinking water issues
SNISHKO, S. (2001): Wasserwirtschaftliche und ökologische Situation im
Dnipro-Einzugsgebiet ... (water management and ecological situation in
the Dnipro river basin) (German) - Hydrologie und Wasserbewirtschaftung
45, 1, p. 1-8
part 2: Table of facts and data concerning the Dnepr River Basin
(Source: ICID webpage, changed)
General geographical data
Source of the River:
Valdai Hills, in Western Russia
Length of the River (km):
Byarezina, Desna, Pripjat
Basin area (km2):
Discharge at mouth (m3/s):
Average Population Density (people/km2):
Percent of Watershed
Hydraulic Structures: Number
of Dams (>15m high) on Main Stem of
Navigation: The river is navigable up to Orsha. Many of its numerous tributaries are also navigable.
Important towns: Dnepropetrovsk, Kiev, Pinsk, Chernigov, Bryansk
Countries in the Basin:
Area in the basin
Percent area in the basin
Dnepr is the third longest European river after Volga and Danube.
Draining the Western portions of European Russia, Belarus and Ukraine,
the Dnepr flows in a generally southerly direction to empty into the
Black Sea near Cherson in Ukraine.
headwaters of the river lie west of Moscow near Sychevka. The source
region is low and swampy, and not suitable for intensive cultivation.
However, the region is connected by an intricate system of riverine
canals connected to Baltic Sea via Western Dvina.
is the major waterway of Ukraine. Just north of Kiev, the river is
deflected in its course by a plateau. Below Kiev, the river enters a
series of rapids.
Dam projects, initiated by the erstwhile Soviet Union, beginning in
1930s, have resulted in creation of several reservoirs that have helped
in navigation of upstream reaches, because of inundation of the rapids.
The mighty Kremenchug dam is located downstream of Kiev.
Zaporozhe, the Kakhovka and Dneprodzerzhinsk dams are a few amongst the
series of dams built on the river. The mighty Dniprohes dam's
hydro-electric station in Ukraine was the largest power station in
Europe, when first built in 1932. The power provided is used in the
large steel making and engineering concentrations in Ukraine. This
concrete dam is 1500 m long and 61 m high with storage capacity of
12.22 BCM and produces about 650 Mw
of power. The river's natural cascades have been transformed into
comprehensive sites of dams, locks and reservoirs. The Kakhovka dam is
the last dam on the river, lying at the lower end of this chain of
hydraulic monuments built along lower Dnepr. The giant reservoirs have
helped improve navigation with the aid of canals joining the river and
many of its tributaries to other major waterways.
Cherson, the Dnepr begins to break up into distributary channels. The
delta is complicated and does not appear as a classic triangular shape.
The swampy lower course of river debouches into a long, narrow estuary
known as the Dnepr Liman, an arm of the Black Sea that receives the
waters of the Southern Bug