Question

how are catastrophic event and hazardous weather alike and different.

Answer 1

Answer:

4.4.2.1.4 Impact of catastrophic events

Catastrophic events, such as wildland fires, flooding, and droughts, can also alter water quality in lakes and reservoirs in ways that affect urban water use. These events alter both the hydrology and transport of chemicals in watersheds, often resulting in large pulses of water, nutrients, sediments, and other chemicals. One particular concern is the impact of wildland fires on municipal source waters. In the US, the number of wildland fires and acres burned on forest service lands have increased dramatically since the mid-1980s (Calkin et al., 2005). These lands alone provide water for water utilities serving 60 million people. Briefly, the effects of wildland fires on water quality include increased water yield and loadings of sediment and nutrients, with mixed findings with respect to metals (Smith et al., 2011; Landsberg and Tiedemann, 2000). The increase in sediment export from burned areas can exceed 1000 times that of unburned areas (Smith et al., 2011). Water from burned areas is often intercepted by storage impoundments. Impoundments may improve water quality, for example, by sedimentation, which would reduce turbidity of water delivered downstream. Conversely, impoundments can exacerbate fire impacts; for example, the pulse of nutrients released from a burned watershed can cause rapid eutrophication of impoundments, with associated impacts on urban water supply (Section 4.4.2.1.2). Water treatment plants below a burned watershed may have to modify their water treatment, switch to other sources (e.g., groundwater), or require residents to boil water (Smith et al., 2011). Given the potential for growing impact of wildland fires on municipal water supplies, there is remarkably little research on upstream mitigation strategies.