flows more slowly into the stream. This may also help in reducing flood waves, and increasing water flow when there is no rain. In other words, beaver dams smooth out water flow by increasing the area wetted by the stream. This allows more water to seep into the ground where its flow is slowed. This water eventually finds its way back to the stream. Rivers with beaver dams in their head waters have lower high water and higher low water levels. By raising the water table in wetlands such as peatlands, they can stabilize a fluctuating water table, which influences the levels of both carbon and water. In a 2017 study of beaver dam hydrology, monitored beaver dams in a Rocky Mountain peatland were found to increase groundwater storage and regional water balance, which can be beneficial for preventing drought. The study also suggested potential to improve carbon sequestration. Excess nutrient removal Beaver ponds can cause the removal of nutrients from the stream flow. Farming along the banks of rivers often increases the loads of phosphates, nitrates and other nutrients, which can cause eutrophication and may contaminate drinking water. Besides silt, the beaver dam collects twigs and branches from the beavers' activity as well as leaves, notably in the autumn. The main component of this material is cellulose, a polymer of β-glucose monomers. (This creates a more crystalline structure than is found in starch, which is composed of α-glucose monomers. Cellulose is a type of polysaccharide.) Many bacteria produce cellulase which can split off the glucose and use it for energy. Just as algae receive energy from sunlight, these bacteria derive energy from cellulose, and form the base of a very similar food chain. Additionally, bacterial populations absorb nitrogen and phosphorus compounds as they pass by in the water stream and keep these and other nutrients in the beaver pond and the surrounding ecology. Pesticide and herbicide removal Agriculture introduces herbicides and pesticides into streams. Some of these toxicants are metabolized and decomposed by the bacteria in the cellulose-rich bottom of a beaver dam. Denitrification Some scientists believe that the nitrogen cascade, the production of more fixed nitrogen than the natural cycles can turn back into nitrogen gas, may be as much of a problem to Earth's ecology as carbon dioxide production. Studies have shown that beaver dams along a stream contribute to denitrification (the conversion of nitrogen compounds back