Small shallow lakes can suffer from too much phosphorus, causing water quality issues. Scientists removed nutrient-rich sediment from a highly eutrophic lake to improve it. This removal reduced the potential for phosphorus release, but high external phosphorus input led to anoxia and internal phosphorus loading. Iron-bound and labile phosphorus were major sources of phosphorus release after sediment removal. The total iron in sediment was linked to phosphorus dynamics. While sediment removal can help, controlling external phosphorus input is crucial for long-term lake water quality.