Which construction element helps control erosion and soil slippage by being staked in place?

The correct choice is live fascines, which are a natural erosion control technique that involves bundles of live branches or twigs that are staked into the ground at an angle. This method helps to stabilize soil surfaces, especially on slopes and areas susceptible to erosion. The live materials not only provide immediate mechanical support to keep soil in place but also encourage the growth of vegetation as the branches take root in the soil. This dual action of providing physical stabilization and promoting plant regrowth makes live fascines particularly effective for controlling erosion and minimizing soil slippage.

In contrast, the other options serve different functions in erosion and stormwater management. Riprap consists of large stones or boulders placed along shorelines, riverbanks, or slopes to absorb and deflect the energy from moving water, reducing erosion but lacking in biological integration. Geotextiles are permeable fabrics used to separate soil layers and improve drainage, but they do not inherently control soil movement like live fascines do. Vegetative cover, while beneficial for erosion control through root systems, does not provide the immediate mechanical anchoring that staked live fascines offer.