Lowland multiple-channel rivers are characterised by floodplain-corridor heterogeneity, high ecological and heritage value, and can be in quasi-stable states. This holistic study of a surviving temperate zone example (Culm, UK) uses geomorphological mapping, ¹⁴C, direct sediment dating (OSL, fallout radionuclides), and palaeoecology. This reveals the evolution of a channel-floodplain system from an initial braided state in the Late Pleistocene to its late Holocene anastomosing state. After the Pleistocene-Holocene transition the reduced channel system incised into its braid-plain, only able to rework gravels locally due to reduced competence in relation to inherited bounding sediment calibre. This resulted in the creation of terrace islands, palaeochannels, and a stable anastomosing pattern dominated by channel junctions, bifurcations and palaeochannel intersections. Survey, coring and excavation reveal a persistence of mid-channel bars and riffles at channel junctions, and where channels crossed palaeochannel fills. In common with most other European lowland rivers this system evolves in the later Holocene due to both climate and catchment changes with a major hydrological critical transition in the mid-Holocene (c. 5300 BP). However, in the case of the Culm, the increase in fine sediment supply often seen in lowland catchments in the Middle-Late Holocene, occurred later, and was insufficient to convert the system to a single medium-low sinuosity channel-floodplain. This allowed the persistence of high heterogeneity and biodiversity (including the persistence of riffle beetles) as part of multiple-scales of non-uniformity. Indeed the pool-riffle persistence is an example of this system’s non-uniformity, being due, at least in part, to the effects of previous channel history. This paper reveals why this river survived in a multichannel state, and by implication, why others did not. These results are being used in the bespoke eco-heritage management of the Culm, but could also inform the restoration of other former multi-channel lowland temperate river systems worldwide.

低地多渠道河流具有漫滩走廊异质性，高生态价值和遗产价值的特点，处于准稳定状态。这项对尚存的温带地区示例（英国库尔姆）的整体研究使用了地貌学制图，[ ^14]C，直接沉积物测年（OSL，放射性放射性核素）和古生态学。这揭示了河道漫滩系统从晚更新世初期的辫状到其全新世晚期吻合的演变。在更新世-全新世过渡之后，减少的河道系统切入其辫带平原，由于与继承的边界沉积物口径有关的能力降低，只能对局部的砾石进行返工。这导致了梯田岛，古河道的形成，并形成了以河道交界处，分叉处和古河道相交点为主的稳定的吻合模式。调查，取芯和开挖表明，在河道交界处以及河道与古河道填充物交汇处，河道中部的条和浅滩持续存在。与其他大多数欧洲低地河流一样，由于气候和集水区变化，该系统在全新世后期演化，并在全新世中期发生了重要的水文临界过渡（约5300 BP）。但是，以库尔姆河为例，中晚全新世低地流域经常看到的细颗粒泥沙供应增加，是在较晚的时候发生的，不足以将系统转换为单一的中低弯曲度河道-滩涂。这允许高度异质性和生物多样性的持续存在（包括浅滩甲虫的持续存在），这是多尺度不均匀性的一部分。的确，池条持续性是该系统不均匀性的一个例子，至少部分原因是先前信道历史的影响。本文揭示了为什么这条河在多通道状态下得以幸存，并暗示为什么其他人没有这样做。这些结果已用于库尔姆（Culm）的定制生态遗产管理中，但也可以为全球其他以前的多渠道低地温带河系的恢复提供信息。