Istra (river)

The first mention of the Istra River dates back to 1461 and is contained in the spiritual letter of Grand Duke Vasily Vasilyevich . In the scribal books of the 16th century, the river is indicated under the names Bolshaya Istritsa and Bolshaya Istra . In later sources, including in the Book of the Great Drawing of 1627, appears again as Istra . In the name, the basis -st- and initial and- can be distinguished, which appeared to facilitate the pronunciation of the basis and has an added character. The ancient Indo-European basis -str , meaning "flow", is presented in Slavic and Baltic terminology and hydronymy ^[3] .

The hypothesis about the Baltic origin of the name is confirmed by the fact that the Lithuanian geographical terms strauja - “stream, current”, srava - “stream, big river”, sraumuo - “stream, fast river”, which correspond to the Latvian strauja, strava, straume with the same meanings , are known . Since the western suburbs, where the river flows, were inhabited by Baltic tribes before the arrival of the Slavs, it is likely that the language of the Baltic tribe that lived on the river had similar terms in terms of str , and one of them could be used as the basis for the name and acquire the form of Istra ^[3] .

A hypothesis is also possible about the Slavic origin of the name. The words jet, strumen, rod, stirrup, well-known in Russian , as well as the names of the rivers Strum, Stri, Styr and the like, flowing in the southern part of the Slavic settlement zone, make it possible to consider the formation of the name Istra . However, preference should still be given to the Baltic version of origin - the larger the river, the more ancient the name is ^[3] .

The Istra River originates on the Moscow Upland , near the village of Koskovo , 2 km east of the Pokrovka platform of the main passage of the October Railway . It flows through the territory of the urban districts of Solnechnogorsk , Istra and Krasnogorsk . It flows into the Moskva River 247 km from its mouth, opposite the village of Znamensky, Odintsovo District ^{[4] [5] [6]} .

Length - 113 km, the area of ​​the basin, including about 190 watercourses with a total length of 885 km, - 2050 km². Among the tributaries of the Moscow River, Istra takes 1st place in terms of basin area and 2nd place in length after Pakhra ^{[4] [7]} .

The Eastern European type of water regime of the river is characterized by high spring floods, summer-autumn and winter low water . Food is mainly snowy and amounts to about 60%, while underground and rainfall account for 28% and 12%, respectively. The average annual water discharge near the village of Pavlovskaya Sloboda (12 km from the mouth) is 12.1 m³ / s, which corresponds to a flow volume of 0.382 km³ / year ^{[4] [8]} .

In 1935, with the construction of 21 km from the mouth of the hydroelectric complex, the Istra reservoir was formed on the river with an area of ​​33.6 km² (at a normal retaining level ), which is part of the Moskvoretskaya water supply system of the capital ^[4] .

After its filling, the water and ice regimes of Istra changed - the period of freezing slightly decreased. High water begins in March - April, ends in April - May, the average rise in water level during this period is 2.5-3.5 m. The water of the river in the lower reaches is characterized as “very polluted” by quality class ^[4] .

The width of the river in the lower reaches is 17–30 meters , the depth is 1.0–1.5 meters , the flow velocity is 0.1–0.3 m / s , the bottom is sandy ^[9] . In the upper reaches it is connected to the lake by the Senezhsky Catherine’s canal , where at the beginning of the 19th century a waterway passed from the Volga along Dubna and Sestra through Senezh, the canal and Istra to the Moscow River. The ichthyofauna is represented by such fish species as roach , bleak , dace , minnow , ruff , perch , bream , chub , gudgeon , char , ide , asp are found in the catches below the Istra waterworks. The river is popular with hiking and water tourists. The city of Istra is located on the river, as well as numerous settlements, motels and rest houses ^{[4] [5]} .

According to the Russian state water register, the river belongs to the Oka basin district , the river basin is the Oka, the river sub-basin is the basins of the Oka tributaries up to the Moksha inlet , the water sector is Istra from the source to the Istra waterworks ^[7] .

(distance from the mouth)

On the river is the Resurrection New Jerusalem Monastery , in the northern aisle of the Resurrection Cathedral of which there is the grave of its founder - Patriarch Nikon. Desiring to make the monastery a new center of Orthodoxy, similar to Palestinian Jerusalem, for greater similarity, he transferred the names of the holy places of Palestine familiar to Christians to the monastery neighborhoods - the nameless stream became the Kudronsky stream , the nearest hills were named Eleon , Tabor and Golgotha , and the villages - Bethlehem , Nazareth , Galilee He began to call Istra Jordan ^{[10] [11] [12] [13] [14]} . The ensemble of the New Jerusalem Monastery is an object of cultural heritage of Russia, as a monument of architecture of federal significance ^[15] .

In 1885, artist Isaac Levitan came to etudes for studies and was struck by the beauty of these places. Subsequently, Istrian motifs were reflected in his paintings “The Istra River”, “Toward Evening”, “On the Traction”, “Birch Grove”, “Golden Autumn”, “Village Maksimovka”, “Landscape” ^[12] .

• List of rivers in the Moscow region

• Libson V. Ya. On the shores of Istra and its tributaries. - M .: Art, 1974. - 144 p. - (The road to the beautiful ). - 75,000 copies.
• Encyclopedic Geographic Dictionary: Geographic Names / Ed. A.F. Treshnikov . - 2nd ed., Ext. - M .: Soviet Encyclopedia, 1989 .-- S. 197. - 592 p. - ISBN 5-85270-057-6 .
• Istra (river in the Moscow region) // Great Soviet Encyclopedia : [in 30 vol.] / Ch. ed. A.M. Prokhorov . - 3rd ed. - M .: Soviet Encyclopedia, 1969-1978.