Cognitive load theory revolves around the limited capacity of working memory (WM) to encapsulate information. While the original theory postulated a fixed capacity of working memory, research in the last decade has provided evidence for the depletion hypothesis. This hypothesis holds that WM becomes depleted after effortful cognitive operations that reduce its capacity, providing a framework for the restorative effects of observing natural scenery. Natural scenery was observed to replenish WM, after this was subjected to depletion. In the present study, participants observed pictures depicting either a natural or an urban environment, after completing a cognitively depleting task. For this study, we obtained EEG measures of working memory, through alpha and theta waves amplitude. The motivation behind this choice was to derive a continuous index of WM capacity and to make up for the lack of electrophysiological data around the depletion hypothesis. Past research identified a decrease in alpha, and a simultaneous increase in theta activity resulting from increasing WM load. Those findings were only partially replicated, as a decrease in alpha amplitude was observed as cognitive load increased, while there was no significant difference in theta power. Moreover, average signal amplitudes did not differ between the natural and the urban condition, as hypothesized. The results point to an absence of the hypothesized environmental effect, opposing the outcome of existing research on the topic. The absence of the effect could also be attributed to a similarity between the two conditions on certain factors thought to elicit the differential physiological response.