**3.5 Eastern Himalayas: Mizoram springs—will they be sustainable in the future?**

 Located in the northeastern states of India, east of Bangladesh (**Figure 6**), this landscape is extremely steep with long narrow valleys. The soils are very thin over shale or sandstone. The vegetation is thick and lush given the monsoon rainfall for 5 months of the year. Even though the landscape is covered in perennial vegetation, the water will only infiltrate centimeters before it enters the sandstone or converges as a headwater stream running off to a river some 2500+ meters below.

People depend on water infiltrating the sandstone and then resurging downgradient as a spring for human use during the non-monsoon season. If the landscape is disturbed by slash and burn agriculture, then less aquifer recharge occurs. The solution requires more sustainable agricultural land use and strategically planned capture of monsoon runoff water. The magnitude and intensity of rainfall during the monsoon season may be shifting in a way that is limiting aquifer recharge to occur. If more water is running off the landscape compared to past decades, then land use must adjust to hold back runoff. This not only means less bare soil but improved soil infiltration and aggregate stability. Topsoil must be highly valued and managed to optimize soil health [19]. In selected ravines, a portion of overland runoff should be laterally diverted wherever a slope break occurs; this practice can provide focused recharge into sandstone aquifers to augment water storage and availability during the non-monsoon seasons.

#### **3.6 Eastern front of Rocky Mountains: alpine to semiarid water law**

Located along the eastern front of the Rocky Mountains in Montana (**Figure 7**), this landscape is weathered due to wind and water erosion. At high elevations (4000 meters+), temperatures remain cool to cold, so vegetative growth is stunted [20].

The region is managed to capture and hold snow for summer water supply to the dry eastern plains. Soils are loamy over metamorphic bedrock, so there is no deep

*Sustainability of Human, Plant, and Aquatic Life: A Theoretical Discussion from Recharge… DOI: http://dx.doi.org/10.5772/intechopen.86171* 

#### **Figure 6.**  *Location of Mizoram in Asia. Source: Google Images.*

 recharge, just overland and interflow to channels that are formed by snowmelt. Near the toe-slope of the range, water can spill into meadows where more organicrich loamy soils are mixed with stratified layers of sand and gravel and cobble, allowing snowmelt water to infiltrate and recharge shallow aquifers. Because of a less steep gradient in places, landowners have dug ditches to divert streams into pasture lands. Both natural and diverted waters resurge in wetlands or springs depending on the geologic constraints. However, the water that does not evapotranspire will move out across the land only to infiltrate into the sediment/soil depending on the nature of the geologic material. This occurs because the source of the water is still snowmelt from high-alpine elevations. Though the water has been geochemically transformed by passing through rock and sediment, it is not groundwater in the sense of an aquifer that provides decadal storage. Further, because this water does not always remain in the stream channel as it flows east downstream, users do not receive the benefits of the alpine water because the water will seep through the channel bed into an aquifer. The new climatic reality demands that water managers examine law and policy to find a sustainable way forward [21].
