Dissertation to receive the degree of M.A.
Natural geography
Climatology trend in environmental planning
Abstract
A flood is a water flow that exceeds the capacity of the river channel and then flows into the adjacent flood plain. Although many local hydrological factors related to the catchment basin may affect the flood, all The main mechanisms that cause floods are of hydroclimatic origin. In general, natural and human factors are effective in the flood phenomenon. The main purpose of the research is to investigate the role of climatic and basin elements and such factors that are effective in the intensification of floods. The studied basin is Masuleh Rudkhan located in Foman city of Gilan province. Library studies and flood studies in the warm period of the year have been one of the main methods of data collection. The results of the research show the humid climate, forest and pasture vegetation, mountainous and foothills, the maximum continuity of flood flow in Kamadel station is 4 days a year and the minimum continuity of flow is 1 day. The highest average flow in Kamadel was in 1377 and the lowest average was in 1376. In order to prevent floods, flood control measures and the creation of delayed dams should be considered.
Key words: flood, climate, climatic elements, Masuleh Rudkhan
Chapter 1
Research overview
1-1- Introduction
One of the types of natural disasters and hazards that cause damage is a flood, a sudden and rapid event. It is destructive and endangers human life and property and creates many problems for the owners of agricultural land and the residents of the banks of rivers and factories. Every year several people lose their lives due to floods. Thousands of cubic meters of fresh water enter the salted waters and leave the water. While every drop of it has vital value. Every year, millions of valuable soil enters the seas and lakes through floods, while it takes decades and sometimes years to form each centimeter. Many of the construction programs of the country's construction minister are affected by this issue A huge amount of the country's budget is spent on rebuilding the damages caused by this phenomenon. Due to the fact that the country has mountains such as the Alborz mountain range, it is a suitable area for the intensification and expansion of this destructive phenomenon, because the mountains act as a barrier against the atmospheric systems and the rivers deviate and are forced to rise, which in this case facilitates the transfer and ascent of the wet air mass and plays an important role in the increase of atmospheric precipitation and as a result, floods. River floods are considered to be one of the most widespread short-term climatic disasters that occur in population centers in clearly defined dangerous areas and require a very different response from humans, that is, the construction of reservoir dams and the teaching of river flooding management methods. Although humans have had to live with floods throughout their lives, the effects of floods on human lives have not been evaluated in the way that is felt today, because in the past small communities At the lower reaches of the Haskeni River, the density of human activities in the flood plains was much less. Meanwhile, today, due to the favorable weather conditions and the benefits of the river banks, people have created settlements and recreation areas around them. Therefore, climatic elements and other factors that affect the occurrence of floods should be investigated, and flood control and management strategies should be developed.
1-2-Statement of the problem and the need to conduct research
Flood is one of the most common natural disasters in Iran because 1-Iran is a mountainous and uneven country, and the streams created from the mountains as soon as they enter the plains and plains of the country spread on the ground and damage fields, gardens, communication lines, villages and cities 2-Plant cover that acts like a sponge to absorb water. slowness is weak in Iran and in many cases it has been damaged due to lack of rain, indiscriminate grazing and cutting of forests. 3- Despite the presence of tropical high pressure centers in most of the regions of Iran in some months of the year, which results in the lack of rainfall for consecutive months, in other months of the year, a significant amount of rain may fall in a few days and a few hours, causing destructive and destructive floods that cause significant damage. in human life and activities, floods and droughts affect different parts of the globe. Our country has witnessed floods and droughts in recent years.In the last few years, our country has periodically witnessed the occurrence of severe floods and droughts in some places, especially that the occurrence of these two phenomena reinforces each other's effects in such a way that due to the occurrence of severe droughts, plant cover and soil moisture are lost, which itself facilitates the flow of destructive floods. (Khorshid Doost, 1384) 4- Severe rainstorms in the hot season in the past years have caused destructive floods in this region (such as the Masuleh flood). Severe summer rainstorms are dangerous phenomena and damage the environment. Identifying the synoptic conditions that cause this rainstorm can help in predicting the time of occurrence and making the necessary preparations. (Alijani, 2014) Therefore, in this research The natural, human, climatic and basin factors that cause floods are investigated. 5- Inattention to the river boundary and construction in its boundary are effective in destroying the river and creating floods, such as the flooding or mudflow in Masuleh, which occurred in the evening of Friday, August 9, 2017. This flood, which caused heavy casualties, killed 54 people and destroyed 48 vehicles and caused damages. The intensity of the mud flood from the Khalil Dasht river area was so fast that it dislodged a light stone slab and hit the bridge at the entrance of this tourist town from a high height, which caused the closure of the water outlet in the river. (Bandi, 1387, 123).
1-3- The main research question
Considering that in this research the climatic parameters affecting the flood of Masuleh Rudkhan are desired, therefore the main question of the research is as follows and the research process is to try to find a suitable answer for it by using the necessary sources and data.
Is Are climatic parameters effective in the flood of Masuleh Rudkhan?
1-4-Research hypothesis
It seems that climatic parameters together with other factors cause floods in Masuleh Rudkhan.
1-5-Research objectives
Investigating and understanding the climatic factors influencing the flood of Masuleh Rudkhan
Knowing the role of the factors Humans in River Floods
Investigating the role of basin elements and such factors that are effective in flood aggravation.
1-6- Limitations of research
The factors that hinder research are called research limitations, which include:
- Lack or lack of accessible scientific resources
- Access to documents such as films or maps is very difficult and to obtain them , the need
commuting and spending a lot of time.
- The non-cooperation of air and government organizations in the field of providing information or the fact that they are not sympathetic in providing information.
Lack of safety facilities in direct observations of the study area
Chapter Two
Research literature
2-1- What is a flood
There are different definitions, including:
High rise of water in a river or channel.
Relatively high rise of water and flooding of lands that are not under water under normal conditions. It was called a flood. (Hojjatizadeh, 2011)
A flood is a water flow that exceeds the capacity of the river channel and then flows into the adjacent flood plain
. Although many local hydrological factors related to the catchment area may affect the flood, all the main mechanisms that cause floods have a hydroclimatic origin. Beshen (Khorshiddoost, 2014, p. 261)
Floods can be divided into two categories
2-2 types of floods
Floods can be divided into two categories:
The first category: these floods are caused by different atmospheric conditions, the instability of rainfall materials.
The second category: in the flood basins due to the lack of coordinated management The unit was created in the basin. (Rezaei, 2018, p. 114)
1-Falsh flood: These floods often occur in the first 6 hours of heavy rain; So that it is accompanied by large cumulus clouds, thunder and lightning, tropical cyclones and the passage of cold air fronts.