6．1855年后黄河下游“地上河”形态逐渐形成，现在黄河下游河床一般比堤外平地高出4－5米，有的地段竟达10米以上，黄河河床因高出两侧平地而成为淮河与海河的分水脊
Since 1855 a river above the surface has been formed in the lower reach. Now, the riverbed of the lower reach is generally 4 to 5 meters higher than the flat field beyond the dam, which makes the riverbed the border between River Huai and River Hai. In some parts, the difference amounts to more than 10 meters.
1484年以前，黄河改道在今黄河道以北，最北曾沿太行山麓北流，再折向东流入海。1484年筑太行堤阻水北流，迫使黄河南流，夺淮河道入海，历经约400年，直到1855年黄河又在铜瓦厢决口东北流，夺大清河由利津入海，即今黄河下游河道。自此以后，人们筑堤防洪，河流泥沙被约束在堤内大量沉积，导致河床日益淤高。现在黄河下游河床一般比堤外平地高出4－5米，有的地段竟达10米以上，河在地上行，下游很少再有支流汇入。河堤成为华北平原的主要“分水岭”，这在世界上是非常罕见的现象。
Before 1484, the yellow river’s riverway was in the north of that of today, and turned to the east to pour into the sea. In the year 1484 the river had to change its way to south taking up that of River Huai because the building of Taixing Dam. About 400 years later, in the year 1855 the yellow river changed its way again to the northeast of Tong Wa Xian, this time occupying the way of River Daqing to pour into sea at Lijin. This is the present riverway of the lower reach.
Since then, people began to build more dams to prevent against floods, which caused the sedimentation of mud and sand on the dam. Thus the riverbed was silted higher and higher. At present, the riverbed of the lower reach is generally 4 to 5 meters higher than the flat field beyond the dam. In some parts, the difference amounts to more than 10 meters. The river runs above the ground. Few branches can join the yellow river. And the dams become major border lines of the North China Plain. This is rare in the world.
由于黄河、海河、淮河的决口、改道，在平原上留下许多纵横交错的古河道、古三角洲和洼地。使平原区的岗洼交错分布，地表形态和沉积物的结构都十分复杂。
The bursts and riverway changes of the Yellow River, River Hai and River Huai left many interlaced ancient riverways, deltas and depressions, which make the surface form and shapes of sediments rather complex.
历史时期，华北平原曾经有众多的湖泊。六世纪初郦道元作《水经注》时，曾有记载。由于黄河泛滥，堆积加速，湖泊也逐渐淤平。如河北的大陆泽（大致在今巨鹿、宁晋、束鹿、深县之间）、山东的大野泽（在今巨野、东平、菏泽一带）等都已被淤平。
In ancient times, there were many lakes on the North China Plain. Li Daoyuan wrote in his book Shui Jing Zhu in early 6 century about the floods, sediments, and filling up of lakes. Lakes such as the Dalu
lake in Hebei province and Daye lake in Shandong province had been silted up.
7．平坦开阔的华北平原是中华文明形成与发展的重要空间
这里不仅是中国古代文化重要产生与发展之地，当前也承载了众多的人口，正创造着巨大的物质文明与精神文明。
The flat and vast North China Plain is an important region in the fostering and development of the Chinese civilization. 三、黄河流域率先进入文明时代，成为中华文明的重要发源地
The Yellow River Region led the step into the civilized age, and became a crucial cradle of Chinese civilization.
（一）黄河文明的形成期（约公元前4000年至－公元前2000年） The Yellow River civilization was formed from 4000 BC to 2000 BC. 1．黄河流域与长江流域因为生存条件适中而在新石器时代取得了长足的进步，并率先迈进了文明的门槛
Both the Yellow River and the Yangtze River gained great progress in the New Stone Age for their moderate living conditions, and led the entry into the civilized era.
中国新石器时代大约开始于距今8000到1万年，结束于距今约4000年左右。一般认为新石器时代有3个基本特征：开始制造和使用磨制石器，发明了陶器，出现了农业和养畜业。
The New Stone Age began about 8000 to 10,000 years ago and ended about 4000 years from now. There are generally three characteristics in this
age: people started to make things and began to use abraded stone tools; pottery was invented; agriculture and stock raising appeared. 中国新石器时代可分为北方文化（阴山、燕山及其以北地区）、黄河流域文化、长江流域文化、珠江-闽江流域文化等区域，黄河流域与长江流域的因为生存条件适中而在新石器时代取得了长足的进步，并率先迈进了文明的门槛。
The New Stone Age can be divided into north civilization (the north of mountain Yin and mountain Yan), the Yellow River civilization, the Yangtze River civilization, and the River Pearl-River Min civilization. Both the Yellow River and the Yangtze River gained great progress in the New Stone Age for their moderate living conditions, and led the entry into the civilized era.
由于北方地区环境的条件过于艰苦，珠江-闽江流域地区环境条件过于优越，而都没有形成足够的向文明社会迈进的动力。例如，在蒙古高原上，植被不繁茂，某些沙漠已经形成，气候干旱少雨，不利于原始农业甚至牧业的产生和发展，属于原始狩猎经济文化类型；处于南端的珠江-闽江流域，水热十分丰沛，植物与水生动物资源丰富，人们可以在迁徙较少的情况下，通过采集、捕鱼手段获得食物，这就难以形成逼使他们发展原始文化的压力，实际上在这里发现的工具大都磨制精细，水生动物是他们的主要食源之一。
The harsh natural conditions of the north and the excellent conditions in the River Pearl-River Min region were actually the resistant force to the civilized society. For example, on the Mongolia Plateau, there was
no luxuriant vegetation, and deserts began to form. The dry climate with little rain was unfavorable to the development of the original agriculture and stock breeding. The River Pearl-River Min region at the north end had enough heat and rain. There were rich sources of vegetations and aquatic animals. People could easily get food by picking or fishing without migration, which presented little pressure to develop their culture. Most of the tools found in this area were abraded finely which indicates that aquatic animals used to be their major source of food.
在黄河流域，第四纪时森林已大量减少，黄土高原已开始形成。在全新世，冰后期造成了干旱少雨的气候，淮河以北的年降雨量在800mm以下，黄土高原的雨量更少，但气候较暖。由于可供采集的植物、果实之类减少，可猎取的动物数量由于猎手日增和手段提高也呈减少趋势，就逼使初民逐渐认识和驯化野生植物（如适于食用、耐干旱、生长期短的野生粟类），同时黄河及其支流为灌溉那些初步驯化的作物提供了条件，使黄河流域成为原始农业在中国的最早源地之一。长江流域的自然条件略好，但许多地区也遇到了北方的那种生计问题。在这种压力下，在南方广泛生长的野生稻也逐渐得到驯化，形成了一个个稻作文化区。 Forests in the Yellow River region have already decreased a great deal in Quaternary age, and the Loess Plateau began to be formed. In Mid Holocene, the climate was dry with little rain. The annual rainfall in the north of River Huai was less than 800 mm. The Loess Plateau had less rainfall but warm climate. With less vegetation and fruits to pick and less animals to hunt (caused by the increase of hunters and much