Which risk increases when natural levees block an oxbow lake's connection to a river?

💡 Explanation

When levees cut off an oxbow lake, stagnant water conditions develop because there is no continuous flow or flushing from the river, promoting nutrient accumulation and algal blooms which drive eutrophication. Therefore, increased eutrophication results, rather than the other changes to groundwater, sedimentation, or stream flows which depend on hydraulic connectivity.

• Which outcome results when barrier islands subside relative to sea level?
• Which process limits the height of natural levees formed along a meandering river?
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• Which mechanism causes a positive feedback effect on glacial melting in high-latitude regions?
• Which mechanism causes increased lake salinity when endorheic basin evaporation rates significantly exceed inflow?
• Which risk increases when a building constructed on permafrost causes thawing of ground ice at the foundation?