Environmental Change in the Moroccan Atlas Mountains

 The Atlas Mountains in Morocco is classified as an extreme environment, with a large seasonal variation in climactic conditions due to the geographical location and the altitude. The 'High Atlas' region, defined as the western massif with peaks reaching beyond 4000m is not classified as a 'semi arid' region as the rain-shadow effect of the mountains provide a relative abundance of precipitation (Merheb et al, 2016). The precipitation however, is not evenly distributed throughout the year and is often sporadic, occurring during events of extreme downpours.

This is particularly true for the Imlil valley in the Al Haouz province of Morocco, and is exemplified by the disastrous 1995 floods when a peak discharge of 1030 cubic metres was sustained for 45 minutes (Saidi et al, 2003). These floods caused extensive damage to the village communities and much of the damage was also visible through scarring on the local landscape as a result of large mudslides. The 'high Atlas' mountains are characterised by steep slopes and relatively loose soil due to a lack of vegetation. These physical conditions alongside the extreme climate result in prime conditions for potential flash floods. In order to address the catastrophe of 1995, communities in the valley engineered practical solutions that would minimise the effects of a similar flash flood event. The primary variable affecting flash floods that the locals could alter was the soil moisture content and stability of the river banks and slopes. Due to the high evapotranspiration rates and lack of vegetation, soil moisture content is highly variable in the Atlas Mountains and modulates soil stability and therefore the magnitude of flash flood events (Tuttle & Salvucci, 2014). 

Figure 1: The beginnings of tree planting projects can be seen at the top of the valley col, and extending down into the valley to offer soil stability (https://www.rediscover.co.uk/activity/imlil-valley-hike).

To address the problems of the local environment mentioned above, large scale tree planting projects were introduced to slopes in close proximity to the tributary rivers of the Imlil valley in order to provide protection in the form of effectively regulating soil moisture content. The tree planting scheme was strategically placed in the higher elevations of the catchment area as this would reduce the amplitude of fluctuations in discharge from a more regular soil moisture content and therefore in theory prevent catastrophic floods on a similar scale to 1995 ( El Khalki et al, 2020). This scheme has drastically altered the environment, in particular the slopes of the upper tributaries which have become greener, particularly when compared to the adjacent valleys of Tizi N'Tachdditt and Tizi Oussem where this type of scheme has not been implemented on the same scale.

Although flooding events still occur due to the nature of the climate, the magnitude of flooding has been reduced by a significant margin with the amplitude of discharge fluctuations decreasing when adjusted for seasonality. In addition to this, the trees are also utilised as an agricultural resource, therefore the scheme has been viewed as largely successful.

On a personal note, I was fortunate enough to visit this location on a school geography trip and it was eye opening to experience first hand the schemes and efforts of the local communities to build resilience to the challenges of the climate and natural hazards.