Sökning: "älvar"
Visar resultat 1 - 5 av 35 uppsatser innehållade ordet älvar.
1. Effects of summer peaks on brown trout and Atlantic salmon growth and survival in hydropower-regulated Gullspång River
Kandidat-uppsats, Karlstads universitet/Fakulteten för hälsa, natur- och teknikvetenskap (from 2013)Sammanfattning : Daily demands for electrical power are met through sub-daily release of turbined water in the form of hydropeaking. Hydropeaking’s changes to stream flow are listed as a threat to biodiversity in river ecosystems as it causes rapid habitat alteration such as increased depth and velocity, affecting the species living downstream. LÄS MER
2. “It was a free and healthy job” : timber floating on the river Ångermanälven in the 20th century
Master-uppsats, SLU/Dept. of Forest Ecology and ManagementSammanfattning : The exploitation of northern Sweden's forests began in about the 1830s and continued expanding northwards over the following decades. A key factor that enabling the exploitation of these forests was the natural infrastructure, such as the network of rivers, creeks and flooding during the summer, which made it possible to float timber from the forests to the sawmills on the coast. LÄS MER
3. Biflödens effekt på mångfald och abundans av växter i strandzonen utmed älvar : Test av hydrochorins effekt och den longitudinella teorin
Kandidat-uppsats, Karlstads universitetSammanfattning : The riparian zone is a changeable and species-rich habitat with important ecological functions that have long been affected by human activities such as hydropower and forestry. Rivers and their adjacent riparian zones also constitute a transport route for plant parts and seeds in a form of passive transport, called hydrochory, which can contribute to the establishment of plants or the preservation of diversity in the riparian zone. LÄS MER
4. Evaluating an increased spill regime as a management tool to improve downstream passage of salmon smolt
Master-uppsats, Karlstads universitet/Institutionen för miljö- och livsvetenskaper (from 2013)Sammanfattning : The anadromous Atlantic salmon (Salmo salar) is dependent on river connectivity to reach spawning and rearing habitats in rivers. Most rivers are today fragmented by artificial barriers such as hydroelectric powerplants (HEP) which impede this migratory movement. LÄS MER
5. Restaureringens effekt på öringpopulationen
Kandidat-uppsats, SLU/Dept. of Forest Ecology and ManagementSammanfattning : Until the 1970s, rivers in Sweden were used for timber floating. In order for the floating to be as efficient as possible, with a minimum of timber getting stuck, many rivers were cleared. Large rocks and boulders were removed from the main channel and tributaries, backwaters and shallow areas were secluded. LÄS MER
