Sentence examples for impassable dams from inspiring English sources

However, over the past ca. 800 years impassable dams have increasingly been established.

Our study sites on both rivers are below impassable dams, each with associated hatchery programs.

Instead, divergence time coincided remarkably well with establishment of water mills and impassable dams in the Medieval from ca. 1200 to 1500.

In the following, we first discuss the reliability of the estimates provided by DIYABC and IMa, and subsequently the impact of the impassable dams on genetic population structure and adaptive divergence.

The two systems historically supported spatially extensive populations of steelhead, but recent estimates suggest that approximately 80% of the natural spawning and rearing habitat is now inaccessible because of impassable dams (McEwan 2001; Lindley et al. 2006a).

The extant NSH population is now subject to a large-scale rehabilitation programme, which involves habitat restoration and removal of impassable dams in rivers along the Danish Wadden Sea coast.

The Fish Barrier Dam, built in 1962, intercepts fish before they reach the base of the impassable Thermalito Diversion Dam and forces them to swim up a fish ladder to the hatchery, which is located on the north bank of the Feather River.

Whereas the first types of water mills built from ca. 1200 may not have completely and permanently blocked the rivers, from ca. 1400 new types of mills became established that involved permanent damming and created impassable barriers [ 39].

Several bridges became impassable and officials had to release water from two major dams to prevent them from overflowing.

Fragmentation problems are particularly severe in freshwater systems [ 8], where the one-dimensional structure of river systems causes dams, weirs and other human-made obstructions to represent impassable barriers to many fishes and invertebrates.

And determined to make it to the Grande Dixence Dam in Valais in Switzerland, I abandoned my car and my wheelchair due to impassable roads and crawled through three-feet-deep snow.