Evaluating land subsidence by field survey and D-In SAR technique in Damaneh City, Iran

Based on the data from piezometers, well logs, geophysical surveys and the interferometric synthetic aperture radar（In SAR） technique, this study investigates the main causes of land subsidence in Damaneh City, Iran. The size, openings and direction of fissures were measured by micrometer and compass. The locations of fissures and wall cracks were determined by GPS. The geoelectrical data were used to determine the composition, thickness, depth and shape of lower parts of the aquifer. Groundwater fluctuations were evaluated by available piezometers. The In SAR technique was used to measure land deformation from space and to map the dense changes of surface displacements. The results indicate that the main cause of ground subsidence is the decline of groundwater heads and changes in composition and thickness of compressible lacustrine sediments. The subsidence map obtained from the radar data of ASAR sensor of ENVISAT satellite shows that the subsidence zone is mainly in northern city that is underlain by very thick fine sediments. The subsidence rates from March to December 2005 and from July 2011 to January 2012 are 6.7 and 7.0 cm/a, respectively. The results also show good correlations among the formation of earth features, decline in groundwater head and thickness of fine-grained sediments. We recommend that the groundwater withdrawal for agricultural and industrial sectors should be restricted and urban expansion in the northern part of the city should be constrained.

Research on Spatio-Temporal Differentiation Characteristics of the Construction Level of Green and Plaza Land in China

Green and plaza land(GPL)is one of the basic elements of urban construction,and is also the most basic public space to meet the needs of citizens for a better life.The exploration on its internal development laws can provide theoretical foundations for the planning of GPL and creating good human settlements.Taking 612 cities in China as the study area and from the"people-land"perspective,this paper selects the total GPL area,the per capita GPL area,and the land use proportion of per capita GPL as indicators to analyze the spatio-temporal differentiation characteristics and evolution rules of the construction level of GPL in China from 1996 to 2016,by using mathematical statistics and spatial analysis methods.The result shows:(1)from a national perspective,the construction level of GPL in China has been rapidly improved along with the temporal evolution,but there is still a big gap from the upper limit of the standard.In terms of the spatial distribution,regional differences have always been great,and the cities scoring below the standard are concentrated in the eastern and central regions,while high-scoring cities are more concentrated in the western region;the distribution of the land use proportion of per capita GPL is in a pattern that the eastern region has the highest proportion,followed by the western region,central region,and northeastern region successively.(2)From the perspective of scale,differences between cities of different sizes exist over a long period of time,and there is an obvious imbalance in the per capita GPL area as well as the land use proportion of per capita GPL between different cities.The construction level shows that small cities have the highest level,followed by medium-sized cities and then large cities.

The Problems of Industrial Land Use in Chinese Cities and Counter—Measures

The concentration of Industries In cities is a commonphenomenon In the course of urhanlzatlon.The reason isIballhe concenlralbn orsndustrles wsuob重alnlhe‘乞concen-traied conomlc returns.” The concentration ofindustriesincities has occupied more land for indutrial use ifthe industri-al land use makes up a very low proportion in the total landuse In cities,the concentrated e门Dciency can not be broughtinto play.Ifthe Proportion is too big,land for other func-nons will be squeezed out,thus affecting the full play of theoverall functions of＊theons urban land.The unreasonable indus-trial land used now exists in Chinese cities.

MLR: Scheme of Establishing Pilots for Rental Housing Construction on Collective-Owned Construction Land Use in 11 Cities Approved

On Jan.25,2018,the Ministry of Land and Resources(MLR)declared that the Scheme of Establishing Pilots for Rental Housing Construction on Collective-Owned Construction Land Use in 11Cities including Shenyang,Nanjing,Hangzhou,etc.,has been approved.MLR emphasized that the pilot areas should follow the principle of house for living,not for speculation.And according