The Final Environmental Impact Statement for the Lava Ridge Wind Project: Visual Resources
The Final EIS analyzed visual resource impacts on dark night skies and sensitive viewing areas. The Bureau of Land Management (BLM) notes that the Project area is given a Class IV ranking, which is applied to landscapes well suited to projects like Lava Ridge.
While the introduction of wind turbines will inevitably alter the visual landscape, the Preferred Alternative offers a significant reduction in visual impacts to sensitive viewing areas like the Minidoka National Historic Site. Under this Alternative, the closest turbine would be approximately nine miles away, a substantial increase from the original proposal’s two-mile setback.
This increase in setback, combined with the lower turbine height, will result in turbines appearing 89% smaller than the original proposal when viewed from the Minidoka NHS.
Figure 1. Current Viewing Conditions at the MNHS Visitor’s Center
Figure 2. Simulated Worst Case Viewing Conditions at the MNHS Visitor’s Center (Moderate Visual Contrast Rating).
The BLM analyzed impacts from numerous key observation points (KOPs) using visual resource ratings and simulations. Under the Preferred Alternative recently released in the Final EIS, 12 of the 17 KOPs had a visual impact rating (Degree of Visual Change) of ‘None’ or ‘Minor”. For reference, the visual impact rating of a ‘Moderate,’ which has a slightly higher degree of change compared to a ‘Minor’ rating, can be seen in Figure 1 and Figure 2.
Impacts to Night Skies
Early in our process, we heard from local stakeholders who wanted to keep their rural skies dark at night. In response, we’ve proposed an Aircraft Detection Lighting System (ADLS) for the Lava Ridge Wind Project to drastically reduce the time when red flashing lights on the turbines would be in use. The ADLS system would allow the aviation lighting on the turbines to remain off more than 92% of the time.
The Final EIS states that dark night skies viewed from the nearby Minidoka NHS are already significantly brighter due to the existing light pollution from Twin Falls, Jerome, other communities along the I-84 corridor, and a nearby maintenance facility. Because of this, full dark adaptation is not possible at MNHS. The Lava Ridge Project would only increase sky brightness at Minidoka NHS by 0.2% to 2.2%, which would not be perceptible to human viewers.