اسم المؤلف:
اشواق عبد الكريم حاتم
اسم المشرف:
عبد الرزاق محمد البطيحي | اسامة خزعل الشريفي
المستخلص:
تناولت الدراسة نهري الكحلاء والمشرح اللذان يمثلا احد الفروع الرئيسة المتفرعة من الجانب الايسر لنهر دجلة ضمن محافظة ميسان، بطول (59) كم لنهر الكحلاء الذي اتخذ اتجاها جنوبي شرقي في جريانه ,واتجاها شرقيا في جريان نهر المشرح وبطول(56كم)،بهدف دراسة خصائص الع | The study addressed the rivers Al - kahlaa and Al - Musharah which represent one of the main branches branching from the left side of the Tigris River within the province of Maysan, a length of 59 km of the river Al - kahla which was taken Southeastern trend in flowing. And oriental trend in the flow of the river Al - Musharah and a length (56 km) the aim of study geomorphological processes prevailing characteristics in the longitudinal sections of the two rivers and identify natural and human factors affecting the activity and work, To highlight its role in the formation of ground features and detected trends geomorphological changes in the flow of rivers and determine the impact of an extension and its evolution the various human activities. The study focused on the field reconnaissance of natural and human factors that affect the functioning of geomorphological processes and identified the causes that led to the fork of the Tigris River from his left side to two branches, The study proved that the geological characteristics of the installation the formative besides regressions morphologies characteristics are responsible for the existence of branches of the Tigris River, because the area constitute a the rivers are lower stream of approximately (3 - 1 m) and represent a natural direction for Land depth, according to Country data flow of the Tigris River water Because rivers Al - kahlaa and Al - Musharah are identical in the direction of flow with the direction of the flow of the Tigris River, and a repeat of flooding in this direction has produced an outlet watery continuously toward the two rivers causing it to the formation of such a course, and especially that the configurations being the rivers are depositions disassembled little of resistance to erosion processes and removal by the flood waves the increase in water season, This is proven by the hydrological study, which showed that the increase in water Al - kahlaa River system follows the natural state of water in the rivers to increase starting in January until the month of May at an annual rate (70 m3 / s), Al - Musharah river human interventions have shown by bridging Amara and rhyming Al - Musharah control evident in the amount the drain by a large margin for Al - Musharah River as it reached the peak of discharge of during the month of May annual rate (17.7 m3 / s) And that this period represents the duty cycle geomorphological and soil erosion or earthmoving work in this stream and then discharges decline starts to begin the two rivers new phase represents a period of low water levels and a weak output and business activity geomorphological the sedimentary and this period is between July until the end of the month of December, Was it studied soil characteristics to identify the their physical properties to determine the extent of its response to the operations geomorphological the existence of a close correlation between the severity of erosion and soil type spun relationship because the soil, the less the content of the muds become less resistant erosion and this factor is very important to explain the disparity in the dredging activity and erosion between the part and the last of stream river and through laboratory analysis of samples of river banks show that the soil mix overcome it alluvials mud, The island's soil has the results of laboratory analysis showed it's completely different in their webs from the banks of the soil as it is of a very high content of sandy soil compared to banks, as it was found to contain a proportion of sands ranging between (70 - 54%) So it is with a soil mixture sandy, well considered human activities of the factors influencing the hydrological and dynamic water in the stream and thus appeared to her reflections on the activity of geomorphological dredging and the sedimentary processes and represented agricultural activity, irrigation, animal husbandry and the activities of the civil rights of (dams and head regulators, roads and bridges), which was a larger role through the its pillars, which occupy a large space of the stream and facing water flowing, which had a role in the revitalization of aqueous deposition stream, The dams and head regulators it may larger role in controlling the hydrological system represented water quantity and discharges and this was reflected on the activity of drift and the sedimentary before the water regulator and several as it has been monitoring the activity even after regulator the output speed and high the troubled water flowing from the regulator, as the increase in stream capacity after regulator (10m) Activity drifting stream capacity is not restricted, but it has spread to affect the depth of the stream, with the increase in the depth of the stream after the regulator (2) m for the same reasons, a high apocenosis and turbulence of the water. Study geomorphological processes focused on the analysis of topographic maps and aerial photos and visual space, along with the field survey has been withdrawn different water samples "the temporal and the spatial" analyzed the laboratory to measure the concentration of loads (soluble, plankton and benthic), Show that the concentration soluble load inversely proportional to the quantity of water and discharges of water in the river that is, they declining in the water increase season and rise in water scarcity season, And also containing ions are of positive and negative such as calcium, magnesium, sodium and potassium in varying proportions content in time and space and the total content makes the water are invalid to drink human according to Global and Iraqi specifications but are valid for irrigation and for all crops and plants. As for payload plankton were measured for calculating on the ground using a device being discharged (Home Made Tools) Show that the highest proportion of the load of plankton measured against the near the surface of the water and diminishing vertically towards the bottom of this is due to the liberation of surface currents and speed that exceed the speed of currents beneath them as evidenced by field measurements ranged discharge loads plankton speed in Al - kahlaa River between (1, 31 - 1,1 kg / s) and ranged quantity (140, 30 mg / l) in the measurement range, (A) near the water's surface, As for Al - Musharah River has a load ranged from plankton (1508 - 67 mg / L) within the measurement range of the near surface As for A discharge load plankton speed ranged between (12.7 - 0.9 kg / s).It was measured benthic load device (Bed Load Transport meter Type Arnhem) for monitoring the movement of sediments every half an hour was the amount of the load of the river bottom Al - kahlaa ranged between (2521.8 - 583.4 tons / year), while ranged in Al - Musharah River (17277.5 - 1003.9tons / year). Was characterized by the processes of sculpture and deposition with varying their activities where he showed the field of measurement and using a topographical map for the year (1980) and the visual space of the year (2013) by measuring the (229) points on the two rivers by 119 measuring points of the River Al - kahlaa and (110) measuring point of the River Al - Musharah Audited measurement on the ground for 10 points, Confirmed the measurements made to (42) points, I noticed a sculptural activity in Al - kahlaa River and 10 points have confirmed the presence Activity sculptural in Al - Musharah River and what remains of the points confirmed the existence of Activity sedimentary which means sovereignty Activity deposition process is clearly on the course of the two rivers. The study focused on the survey and analysis of the morphology of the Stream bed by a device (ADCP) to determine the geomorphological work directions and points of impact in the stream, Has been longitudinal sections and occasional Drawing of two rivers and their branches by 390 measuring points were identified to measure its dimensions and characteristics of the future and their impact, by checking out the space visuals and modern topographic maps and field surveys indicate the presence of multiple river manifestations such as cornering the river where they were monitored (37) turn and twisting and carrot river (9 guestrooms) and tongues fluvial (river banks of the updated) of (19) of the tongue has been measured dimensions and determine the factors responsible for the its formation, The study revealed a river delta of the River Al - kahlaa shaped my finger (foot the bird) were quantified lengths of the branches and the plains of the delta area and the rate of decline of the delta plains and the direction of the gradient. It resulted in the total hydrological changes and geomorphological during the period (1980 to 2013) of the establishment of the helm Amara and head regulators Al - kahlaa and Al - Musharah and pounded the old dam (1992), a series of fundamental changes in the geomorphological status of stream and the impact of natural and human factors, and that left the various its effects and visible fingerprints in the dimensional morphological manifestations ground in the two rivers.
