Developing a Stochastic Hydrological Model for Informing Lake Water Level Drawdown Management
Winter Drawdown (WD) is a common lake management technique involving the artificial lowering of water level during cold winter months. It is typically used for a variety of purposes, including the control of unwanted aquatic vegetation. Government agencies may provide general guidelines to reduce potential damage from WDs to lake ecosystems. For example, Massachusetts guidelines require WD lakes to adhere to stipulations regarding drawdown/refill timings while maintaining their outflow rate within a given range. However, because every lake is somewhat unique and annual weather conditions may be highly variable, it is difficult to determine if a WD lake can achieve these state-mandated requirements.
To facilitate the use of this management approach, a team including NE CASC investigators Kostas Andreadis and Allison Roy developed a hydrological model for lake drawdown management (HMF-Lake) and applied it at 15 Massachusetts lakes where WDs have been conducted for years. Results from their study are detailed in a new article, “Developing a stochastic hydrological model for informing lake water level drawdown management,” published in the Journal of Environment Management.
Ultimately, the model was used to calculate the probability that each lake in the study would be able to conform to state requirements. Moreover, because lake managers may be uncertain when they should initiate a refill to comply with the state’s annual refill deadline (April 1), the model also helped estimate the latest refill starting date that would allow managers to meet the deadline.
All things considered, this model can help lake managers understand whether or not they can implement a WD and how to better manage the drawdown/refill process. Government agencies can also use this model to determine if state refill guidelines will remain valid in the face of anticipated climate changes.