Lenne

{{Short description|River in Germany}}

{{Other uses}}

{{Expand German|topic=geo|date=January 2018|Lenne (Ruhr)}}

{{Infobox river

| name = Lenne

| image = Letmathe-Lennebruecke1-Asio.JPG

| image_caption = The Lenne in Iserlohn-Letmathe.

| source1_location = Sauerland

| mouth_location = Ruhr

| mouth_coordinates = {{coord|51|24|54|N|7|29|31|E|display=inline,title}}

| progression = {{PRuhr}}

| subdivision_type1 = Country

| subdivision_name1 = Germany

| length_km = 129.0|length_ref={{GeoQuelle|DE-NW|GSK3C}}

| source1_elevation = {{convert|819|m|abbr=on}}

| discharge1_avg = {{convert|25|m3/s|abbr=on}}

| basin_size_km2 = 1,355|basin_size_ref={{GeoQuelle|DE-NW|GSK3C}}

| tributaries_left = Else (Lenne), Bigge (river), Elspe (Lenne), Grafschaft (Lenne), Uentrop (Lenne)

| tributaries_right = Nesselbach (Lenne), Nette (Lenne), Sorpe (Lenne)

}}

The Lenne ({{IPA|de|ˈlɛnə|-|De-Lenne.ogg}}) is a tributary of the river Ruhr in the Sauerland hills, western Germany. It has caused flooding in recent years.{{cite journal|first1 = H. | last1 = Gôppert | first2 = J. | last2 = Ihringer | first3 = E. J. | last3 =Plate | first4 = G. | last4 = Morgenschweis|date=April 1998|title=Flood forecast model for improved reservoir management in the Lenne River catchment, Germany|journal=Hydrological Sciences|volume=43|issue=2|page=215|doi=10.1080/02626669809492119|citeseerx = 10.1.1.408.1817 }}

Having its source on top of the Kahler Asten near Winterberg in an intermittent spring at an elevation of {{convert|2,687|ft|abbr=on}}, the Lenne ends after a course of 129 km flowing into the Ruhr river near the city of Hagen. With an average discharge of 25 m³/s near its mouth, it is the main tributary of the Ruhr. {{citation needed|date=February 2015}}