Section B Answer one question from this section. (a) Study Fig. 4.1, which is information about flooding which was predicted for the area around the Mississippi River, USA, in December 2015. N Quincy Mississippi Springfield Illinois Decatur Columbia Missouri St Louis Meramec Mississippl 0 Key 50 100 km major flooding moderate flooding minor flooding urban area of St Louis settlement direction of flow Cape Girardeau Kaskaskia [Figure 4.1]

Mark scheme

Marking points from the official mark scheme (Oct/Nov 2019). The mark or mark type is shown in brackets.

1. [1] St Louis is at the confluence of the Mississippi and Missouri.
2. [2] Ideas such as: It is (further) downstream/at/nearer mouth; Several tributaries have joined the Mississippi by then; It is likely to have a large flood plain/flat/low land around the river.
3. [3] Impacts such as: Roads/railways/bridges flooded/impassable/destroyed; Farmland flooded/loss of crops/food shortages/soil eroded; Farm animals die/drown/need to be rescued; Loss of lives/people drown; Electricity supply disrupted; Water supply contaminated/waterborne diseases or example; Homes/buildings/villages/settlements/personal possessions destroyed/flooded; Natural vegetation/trees/habitats/wildlife destroyed; Fertile soils/land, etc.
4. [4] Ideas such as: Build a dam/reservoir (upstream); Levees/embankments/barriers; Sandbags; Dredging; Overflow channels; Use sluice gates/spreading areas upstream; Straighten the river/line with concrete; Tree planting/reduce deforestation; Monitoring/prediction/early warning/alarms/evacuation; Land use zoning/keep grassy areas near rivers; Build on stilts/housing design, etc.
5. [3] Characteristics such as: Curved/horseshoe/crescent/semi-circle/backward C; North-south orientation; Long and thin; Width approximately 0.5 to 1 km; Length approximately 10–16 km; Small island; Wider in middle/south/narrower at ends, etc.
6. [5] Ideas such as: River flows around a meander/formed from meander; Erosion on outer bends; Due to faster flowing water; Hydraulic action/abrasion (or description of process); Helicoidal/helical flow; Deposition on inside bends; Due to slower flowing water; River becomes more sinuous/winding/extreme meander; Neck of meander reduced in thickness; Eventually river erodes across neck/river flows straight on/cuts off meander; During time of flood; Deposition seals former meander, etc.
7. [7] Comprehensive and accurate statements, including some place specific details. Content Guide: Answers are likely to refer to: Fertile soils, Transport routes, Flat land, Domestic water supply, Irrigation, Fishing, Jobs in tourism, Jobs in industry, etc. Place specific reference is likely to consist of: Locational details, named places alongside river/country name/area, etc.