Vyksa Nizhny Novgorod Region
§ 8. Coast and education in the mainstream.
1. Concave coast and its elements.
The floodplain concave shore, which is steep due to the constant washing off of it by a pressure current, is called a spring. Yar depth is always greater than the opposite convex shore. This makes it possible for navigators to carry out transport vessels with a large draft on a sea bed, i.e., near a concave coast. Yar begins (and ends) in the place where the concave bank passes into a straight section of the river or into a convex bank. The beginning of the yar is called the upper shoulder of the yar, and the end, which is located downstream, is called the lower shoulder.
Fig. 13. Unclean Yar: 1 – Yar; 2 – Yar brow; 3 – water edge; 4 – a fallen tree; 5 – underwater stove
The line of transition of the surface of the earth into the steep bank is called the ridge of the yar (Fig. 18). Sailing can be obstacles to navigation, which reduce the guaranteed depth. Such obstacles include the pechina, a part of the rock that is difficult to wash out (usually clay), which goes into the mainstream. Near Pechina, as in general from the spring, there is a fast current and great depth. Pechin can be surface and underwater. Above the pechin a backwater is created, and below — a circulation (subs). Judgment is judged on the location of the underwater furnace.
If there is a forest on the bank at the beach, it means that there may be karches in the water, which are formed from trees and stumps falling into the water as a result of the destruction of the coast being washed.
Serious obstacles to shipping, which are almost impossible to determine by external signs of terrain and flow, are the club and pobochen.
The club is called the horizontal platform of the unbreakable soil in a bow under water. The location of the club should be known to the master, the water horizon is changing on it.
Pobochni – sediment sand at Yar – formed from the discharge of water during high water from the flooded floodplain into the mainstream through Yar. By forming in the banks of the excavation from the discharge of water from the floodplain, you can determine the location of the subsurface immediately after its formation. Especially, there are a lot of cases in the rivers after the flood, when the river enters its banks. Most often, the water is washed out completely or partially by the water of the low-water channel. On the locked river, the water is washed out more slowly than on the free one. As a rule, sediments are deposited below the drywater due to the weakening of the flow, i.e. small sprays are formed.
Yar is called an unclean yar, near which there are various underwater and surface obstacles for navigation near the coast: pechins, clubs, Karchi, pobochni, oditsy, etc. The movement of ships near such a shore is dangerous.
If the yar has no obstacles for navigation, it is called pure yar.
2. The convex shore and alluvial deposits near it.
The sediments in the river flow under the action of the flow move in a straight line passing through the convex banks at the bend of the ax channel and along the entire width of the channel in relatively straight sections (Fig. 14). Fig. 14. Displacement of sediments in the river bed and formation of shallows (1, 2, 3) and stretches
At convex shores, where the flow is slow, sediment is deposited. Significant sediment deposition forms a low, sandy beach without vegetation, called sand. The shape of the sand usually corresponds to the outline of the opposite sand.
The main type of sediment deposition of sand is a spit (Fig. 15), which is of considerable size, triangular in shape, the base adjoins the convex bank and the apex gradually passes from the surface to the underwater state. The spit of small size, adjacent to the spit or directly to the convex bank, is called a zakok. A large underwater spit, extending far into the river bed, is called the zamaniha. The sand or spit under the action of the current can be strongly eroded and become steep near the “upstream” (upstream) part of the current, which is why the fairway usually passes through a deep place. This sand or spit called trim and. A group of underwater braids, small in size, is called a sstrug. Zastrugi adjacent to the braids, zakoskam and can be located separately in the mainstream.
Zatoninoy is a small bay in the river behind the spit. The inflated formations of the convex bank, spit, barbs, etc., due to the constant work of the flow, change their size, are subject to erosion or, on the contrary, increase.
3. Applied education in the mainstream.
In addition to sediment near the convex bank and the side of the river, there are other alluvial formations in the riverbed, surrounded by water, both underwater and above-water. These include islands, islands, landings, shalygi.
The center is a surface shallow, surrounded on all sides by water and having no vegetation.
Fig. 16. Ship broke, on a shallow
From the erosion of the underwater part of the spit may form an underwater center; it may also occur below the cape of the arrow, formed from the confluence of two rivers, in the tikhovod, behind the mountain market, on shalyg and various underwater obstacles. Seedlings limit the width of the channel, change the direction of the flow of water.
An island is a surface center with vegetation. The island can be formed from the middle, the floodplains, due to the straightening of the bend, the division of the channel into two branches, the formation of a blockhole – a narrow branch dividing the island into two separate islands. The upper part of the island and the center, eroded by the flow, is called the top, the lower part, where sediment is deposited, is a rod.
Shalygoy is the name of the underwater sedimentary deposition at the side of the hull of a vessel that has become stranded across the trough of rolling (Fig. 16), i.e., has been taken.
After removing the vessel from the ground, the current bypasses shalygu, eroding it. Gradually, the shalyga can be torn down by the current closer to the basement of the rolling stock and change it, forming an embarrassing rollback with a convex basement. Shalyga can also hold sediment, increasing in shape and turning into center.
The outflow of sediments carried out of the tributary (river, stream, ravine, etc.) in the mouth or below it is called discharge. The outflow consists of gravel, sand, pebbles, and sometimes stones.
If the tributary flows into the concave bank, then the discharge that is located in the bed near the mouth of this tributary is at the same time. If the inflow flows into a convex bank, then sediment deposition at this bank increases. The outflow area is usually larger if it is below the inflow, and smaller if it is formed by the arrow.
The amateur boatmaster should foresee the possibility of the formation of a discharge when approaching the coast below the inflow or entering it and lead the vessel at a slow speed, measuring the depth with a basting (meter rod).
4. Unbreakable obstacles.
There may be a large number of unbreakable obstacles in a river. These include:
Odinets is a separate stone of considerable size lying in the river. Odinets, frozen in the ice, can move along with the ice during ice drift over long distances.
Ogrudki (rocky center) – a cluster of stones extended along the coast or an underwater part of a monolithic rock massif in the channel.
The ridge is an underwater cluster of stones in the riverbed across the river.
The threshold is an underwater and above-water accumulation of large stones along the entire width of the channel, creating water retention above the threshold and a rapid flow in the threshold. The fairway of the river at the threshold is usually shallow, winding and passes between the underwater and surface stones.
Shivera, a type of sill on the Siberian rivers, is formed by groups of stones scattered in separate areas along the entire width of the channel. Fairway meanders between them.
When sailing on inland waterways, the amateur navigator should know some more pilotage terms.
Delta – the place where the river flows into the lake or the least. The river in the delta usually forks into several small ducts, branches. The delta has the form of a triangle resembling the Greek letter delta. The triangle is directed towards the sea by its base. Delta is formed due to sediment deposition.
The estuary is a network of gaps that form the river delta. The estuary is usually called the channel in the deltas of the Dnieper, Dniester. On the Volga, they are called Eriks, on the Danube – by beads, on the Northern Dvina – by sleeves. Sometimes the channels in the delta are very wide, then they are called ilmenyas (on the Volga), flowing (on other rivers).
The water boundary is the line of intersection of the water surface with the shore.
The splash is a narrow, usually sloping shoreline, flushed with excitement, adjacent to the water’s edge.
Volozhka is the second riverbed, separated from the main (main) channel by the island. Volozhka over time can become the main course of the ship.
Guaranteed depth – the smallest depth, the maintenance of which is guaranteed in this area due to dredging, release of water from reservoirs, straightening structures.
The raid is the water area (water area) of the port, where the vessels are waiting for loading and unloading, tow structures are formed and disbanded, vessels are defended in a storm and during repairs.
Dam – hydraulic engineering rectifying structure, which serves to change the flow, the continuation of the coast, the fence from the waves or ice drift.
The sediments in the river are arranged in a straight line of their movement connecting the convex shores, forming an oblique transverse shaft in the channel. This driftwood, above which the water depth is less than in adjacent parts of the channel, makes shipping difficult and forms rolling with its shallow water (Fig. 17). Between the shallows are deep-water sections of the river – reach.
The shaft, or the saddle of the rolling line, at the intersection with the rod, is eroded and it produces a recess, called the rolling trough, where the greatest depths are located on the rolling line. On the roll trough passes the ship passage.
The upstream sloping part of the rolling saddle is called the pressure head. The lower part of the saddle is steep and is called the basement. Above the basement is the smallest shallow depth. The uppermost part of the basement is called the ridge. The degree of difficulty in escorting vessels through the rolls depends on the shape of the basement, the depth, direction and speed of the current on the roll.
Fig. 17. Roll: 1 – upper spit; 2 – lower spit; 3 – upper stretch hollow; 4 – bottom stretch hollow; 5 – saddle of rolling; 6 – recess trough; 7 – pressure head; 8 – basement roll; 9 – roll comb; 10 – fairway
The deep-water part of the river, adjacent to the shallows, is called the flood plain and is the beginning or end of the next reach.
The upper and lower spit rolls (or sands) are located above and below the rolls trough. On the shallows, the ship’s passage, as a rule, passes or, as they say, passes from one bank to another. These places are called passes mi.
Due to the significant difference between the draft of the vessel and the depth of the fairway on navigable rivers, the amateur navigator does not always feel the shallow waters of the shallows, but, as a rule, the amateur’s vessel feels the changes and intensification of the current during the shallow. In sailing, it is necessary to know and anticipate the degree of difficulty of passing through one or another roll of oncoming and overtaking ships that can arbitrarily change their course of travel — to scour.
When an amateur drives his vessel along a non-navigable river or river, where timber is floated, only his ability to determine the recess trough, discharge of water, the shape of the basement and knowledge of shipping qualities allows one to navigate his vessel without running aground and without accidents.
The rolls are very diverse, they differ from one another by location in the mainstream, elements in the plan and profile, and the hydrological regime. The degree of difficulty in navigating shallows depends on their properties.
There are several navigational classifications of shallows, so let us dwell on the characteristic features of some shallows, the knowledge of which is necessary for an amateur master.
A roll with a flat basement (according to the classification of D. A. Bogdanov) is called such a roll, the shaft of which is located across the fairway across the entire width of the trough in a straight line from the upper roll to the lower spit. The flow is uniformly uniform over the entire width of the roll trough. Shipping quality is favorable. Vessels proceeding from the bottom must be entered at the basement of the rolling so that the diametrical plane of the vessel coincides with the direction of flow, for which the exit of the vessel on a straight course to follow along the roll of the trough should be carried out as early as possible.
Fig. 18. Shallow stream with a convex basement
A roll with a convex basement according to the same classification is most often formed where a lot of sediment is carried by water, where the bed erodes, and especially the spring. The deposition of waste in the middle part of the basement leads to its bulge in the plan and profile. The convexity of the basement occurs at the expense of a more or less significant basement center in the center of the basement, where the smallest depths are usually found. Therefore, the current on the rift is fan-shaped and there is no pronounced main jet – rod (Fig. 18). The shipping qualities of such a roll are bad, as the fairway can change its direction either from one side or the other from the bulge of the basement. The fan-shaped current knocks the ships off course towards the borders of the fairway (to the shores).
Perekat “placer” (according to the classification of I. Popkov) is located mainly in the lower reaches of the rivers. It is formed with braid bars lying on opposite banks and shalygas. There are several basements and usually they have an irregular shape. The roll often changes. Sastrugs, shalygi, the middle forms an irregular flow, which causes yawing of ships. Because of the vaguely expressed basement, the passage of ships through such a roll is difficult and it is recommended to walk along it, measuring the depth.
Wellhead rolls (according to the classification of I. F, Popkova) are formed during floods, when water from the main river enters the tributary, bringing in its sediments, where they are deposited. In addition, water retention in the tributary delays the movement of water in it, which contributes to sedimentation of sediment. With the recession of water after high water, these sediments form in the tributary, above its mouth, estuaries, which sometimes stretch for several tens of kilometers. Spit, surface and submarine islands, islands that the tributary water cannot wash off into the mean water are also formed. Wellhead rifts usually make shipping very difficult.
An amateur often begins his tourist trip in a non-navigable tributary, which flows into the navigable river. Therefore, it is important to find out if there are estuary rifts in the mouth of a tributary, what is their depth and whether an amateur vessel can pass through these rifts.
If it is impossible to pass into the navigable river during low water, then you need to know the dates when low water begins, in order to organize a hike earlier and go through the mouth rifts to the minimum water level on them. At the mouth of the shallows, the horizon may be increased due to the outflow of dams, which are present both in the main river, above the mouth of the tributary, and in the tributary.