M.R. Goodarzi; R. Piryaei; M.R. Moosavi
Abstract
Introduction: Due to climate change that is happening, the security of water and food in Iran has caused many worries, which include small towns like Boroujerd. A comprehensive assessment is necessary as well as the productivity of water resources, because it can provide information for government ...
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Introduction: Due to climate change that is happening, the security of water and food in Iran has caused many worries, which include small towns like Boroujerd. A comprehensive assessment is necessary as well as the productivity of water resources, because it can provide information for government agencies and the public to develop appropriate patterns. The aim of this study is the use and productivity of water resources in Borujerd city, the aim of this study to utilize appropriately the existing water resources in the city of Boroujerd and it is based on recycling and reusing water resources and reduced harvesting of ground water. So the potential of water saving and return to the cycle has been evaluated, and the results can be used as a potential solution for water shortage in Boroujerd in the future.
Materials and Methods: Water, energy, and food security globally are achieved through a communication approach, an approach that integrates governance and management into all over sectors and scales. A communication approach can support the transition to a green economy which aims instead, among other things, the use of resources and policy coherence. Given the increasing communication between sectors in space and time, reducing economic, social and adverse environmental concerns can increase overall resource efficiency, more benefits and provide human rights for water and food. Therefore in a relationship-based approach, common policy and decision making an approach which reduces the composition and creates collaboration among sectors is in need.
Currently, the most reliable tool to produce climate scenarios is the paired 3D Atmosphere-Oceans General Circulation Models which called AOGCM in this paper. AOGCM is based on the physical relationships that are presented by mathematical relations. In formulating its AR5 synthesis report, the IPCC has made use of new RCP scenarios of greenhouse gas (GHG) emissions. The IPCC society has used new scenarios as trajectory representatives of various concentrations of greenhouse gases. New scenarios have four key trajectories called RCP2.6, RCP4.5, RCP6.0 and RCP8.5 that are based on their radiative stimulus in 2100 and different specifications of the technology level, social and economic situation and future policies.
LARS-WG is a random weather generator that can be used to simulate atmospheric data at a station under current and future climate conditions. The first version developed in Budapest in 1990 as part of an agricultural risk assessment in Hungary, then reviewed and moderated by Semenov in 1998. This model produces a daily time series of minimum and maximum temperature, rainfall and solar radiation.
Results and Discussion: Concerning precipitation variations, it can be concluded that changes in winter months from January to March in RCP2.6 will decrease by 20%. Rainfall variations in the spring are the same and have equal status with the base time. In summer, two scenarios experience a 40% reduction, in fall, RCP2.6 shows a 20% increase in rainfall and the scenario RCP8.5 shows about 10% precipitation reduction. The two scenarios show at least 1.5 degrees Celsius increase and the highest increases are in fall, and in October, a rise of 2.5 degrees has seen. Maximum temperature changes which indicate the temperature increase to 2 degrees at least in both scenarios. In scenario RCP8.5, in winter and fall, the maximum temperature is increased to 2.5 and 3 degrees, respectively. Boroujerdʼs water and sewage company harvests 22 hm3 (MCM) water annually for its population of 240,654 people. If the necessary measures are taken for gray and black water purification, Boroujerdʼs daily city sewage that is 35416/6 m3 daily, can return to the water cycle. The city's total wastewater is 12,750,000 m3 per year and it is possible to prevent underground water harvesting with purification. Rainfall is another important resource never utilized in Boroujerd. The gable roof and those with more than 15 degrees gradient can be used to collect the rainwater in the high rainfall season. The total roofs are 136.13 ha and according to the average rainfall 0/454m, it can be the maximum use of this resource. The annual volume of precipitation for this city is 612612/45m3 which is significant. Supposedly, it could provide 3.6% of fresh water. Also, if the volume of sewage is considered for purification, the amount of available water source reaches 13362612/45m3 which can meet 60/74% of current water demand.
Conclusion: Rainwater is not used as a natural resource in Borujerd city and flows into seasonal rivers as runoff. It can be said that harvesting rainwater is an opportunity to reduce water shortage in the future. Rainwater system transferred through the water pipelines and sewage system. It is possible to store rainfall and water remained after snow melts for dry seasons and its surplus can be used to supply. Also due to climate changes and agriculture in Borujerd city, a plan should be provided to reduce the use of water in the summer which is expected to be implemented shortly.
Mohammad Reza Goodarzi; Alireza Faraji; Mahdi Komasi
Abstract
Introduction: Uncertainty estimation of climate change impacts has been given a lot of attention in the recent literature, However, uncertainty in downscaling methods have been given less attention. Today many studies have been done about the future impact of climate change on human life and water resources. ...
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Introduction: Uncertainty estimation of climate change impacts has been given a lot of attention in the recent literature, However, uncertainty in downscaling methods have been given less attention. Today many studies have been done about the future impact of climate change on human life and water resources. Urban development, water conflicts, and Green House Gases increasing will intensify this event in future and will alter rivers flow. Basin catchment has faced to flow recession and also runoff decreasing in few last decades. At this field the climate change effects will intensify this conditions in future decades too. The first step of climate change impacts studies is the projection of future climate variables (e.g precipitation and temperature). GCMS models and their outputs are useful tools for this projection. The main problem is the mismatch of spatial scale between the scale of global climate models and the resolution needed for impacts assessments.
Materials and Methods: The Gharesou River Basin is located in the west of Iran. Its area is approximately equal to 5793km2, and the maximum and minimum of its heights are 1237 and 3350 m, respectively. The average of annual rainfall varies from 300 to 800mm. This study focuses on various climate models from IPCC fourth and fifth reports and has been used two downscaling methods including the statistical and proportional downscaling methods and also scenarios and different climate models for considering different uncertainty. The new scenarios as Representative Concentration Pathways (RCPs) of greenhouse gasses have been used in fifth assessment reports (AR5) of IPCC. The Representative Concentration Pathways describe four different 21st-century pathways of greenhouse gas (GHG) emissions and atmospheric concentrations, air pollutant emissions and land use. The RCPs represent the range of GHG emissions. Different kinds of downscaling method include 1) Proportional downscaling that is adding coarse-scale climate changes to higher resolution observations (the delta approach); 2) Statistical method (eg SDSM model; CLIGEN; GEM; LARS-WG and etc); 3) Dynamical method that is application of regional climate model using global climate model boundary conditions (e.g, RegCM3; MM5 and PRECIS). statistical downscaling method processes establish relating large scale climate features (e.g., 500 MB heights), predictors, to local climate (e.g, daily, monthly temperature at a point), predictands. The SDSM software reduces the task of statistically downscaling daily weather series into seven discrete processes that are consist of quality control and data transformation; screening of predictor variables; model calibration; weather generation (observed predictors); statistical analyses; graphing model output and scenario generation (climate model predictors). HEC-HMS (Hydrologic Modeling System) has been designed by HEC (Hydrologic Engineering Center) for simulation of precipitation-runoff processes in a drainage basin. The HEC-HMS simulation methods represent - Watershed precipitation and evaporation: These describe the spatial and temporal distribution of rainfall on and evaporation from a watershed. - Runoff volume: These address questions about the volume of precipitation that falls on the watershed: How much infiltrates on pervious surfaces? How much runoff of the impervious surfaces? When does it run off? - Direct runoff: including overland flow and interflow. These methods describe what happens as water that has not infiltrated or been stored on the watershed moves over or just beneath the watershed surface. Baseflow: simulate the slow subsurface drainage of water from a hydrologic system into the watershed’s channels.- Channel flow: These so-called routing methods simulate one-dimensional open channel flow, thus predicting time series of downstream flow, stage, or velocity, given upstream hydrographs. HEC-HMS includes several models for calculation of cumulative precipitation losses but only the SMA module is continuous (a module that simulates the losses for both wet and dry weather conditions). Other loss models are event based.
Results and Discussion: The results of criteria and models weighting show that CANESM2 and HADCM3 are better than other models for future temperature and precipitation projection for statistical downscaling and HADCM3 for future precipitation and HADGEM for future temperature assessment for Proportional downscaling. According to various scenarios, future temperature and precipitation projection (2040-2069 period for the statistical and 2040-2052 period for Proportional downscaling) have downscaled and have given to HEC-HMS model for future flow projection. Already the rainfall-runoff model has calibrated and validated base on observed flow data in reference period that daily coefficient of determine was 0.7 for calibrated period and 0.6 for validated period. Finally, flow variation has investigated that Most of GCMS represent increases in winter flows and reductions in other season flows.
