Flumenthal is a municipality in the district of Lebern in the canton of Solothurn in Switzerland. The Flumenthal dam was erected in the 1970s on river Aare during the Second Jura water correction in order to regulate the waters of the Seeland's three lakes hydrological system further downstream of the regulating dam Port. Flumenthal has an area, , of . Of this area, or 48.9% is used for agricultural purposes, while or 24.8% is forested. Of the rest of the land, or 19.6% is settled (buildings or roads), or 5.5% is either rivers or lakes and or 0.6% is unproductive land. Of the built up area, industrial buildings made up 1.3% of the total area while housing and buildings made up 7.1% and transportation infrastructure made up 6.8%. while parks, green belts and sports fields made up 3.5%. Out of the forested land, 21.9% of the total land area is heavily forested and 2.9% is covered with orchards or small clusters of trees. Of the agricultural land, 33.8% is used for growing crops and 14.5% is pastures. All the water in the municipality is flowing water. The municipality is located in the Lebern district. The northern part of Flumenthal lies on a gravel terrace that was built up by the Aare river, while the southern part lies along the river. The blazon of the municipal coat of arms is Gold a Moor's head with Headband and Collar Silver and Lips Gules. Flumenthal has a population () of . , 8.5% of the population are resident foreign nationals. Over the last 10 years (1999–2009 ) the population has changed at a rate of -4%. Most of the population () speaks German (956 or 95.0%), with Albanian being second most common (11 or 1.1%) and Italian being third (10 or 1.0%). There are 2 people who speak French and 1 person who speaks Romansh. the gender distribution of the population was 50.1% male and 49.9% female. The population was made up of 446 Swiss men (45.2% of the population) and 48 (4.9%) non-Swiss men. There were 458 Swiss women (46.4%) and 35 (3.5%) non-Swiss women. Of the population in the municipality 306 or about 30.