CH Ecosystem Restoration 3

Question 1

What hydrologic function does a floodplain reconnection project primarily restore?

Accepted Answer

Lateral hydrologic connectivity that attenuates floods and recharges groundwater

Answer

Floodplain reconnection restores lateral connectivity, allowing flood waters to spread, slow, and infiltrate, reducing downstream peak flows and recharging alluvial aquifers.

Question 2

A Rosgen Level II survey classifies a reach as a C4 stream type. Which characteristic set defines this classification?

Accepted Answer

High sinuosity, low gradient, gravel substrate, well-developed floodplain

Answer

Rosgen C streams are high-sinuosity, low-gradient channels with well-developed floodplains; the '4' suffix denotes a gravel-dominated substrate.

Question 3

Which remote sensing product is most useful for mapping pre-restoration tidal wetland extent to establish baseline conditions?

Accepted Answer

Historical aerial photography and topographic charts combined with LiDAR DEMs

Answer

Historical aerial photography and topo charts define pre-disturbance conditions, while LiDAR DEMs provide current elevation needed to model tidal inundation.

Question 4

In a tidal marsh restoration following dike removal, which process most rapidly re-establishes sediment accretion?

Accepted Answer

Tidal import of suspended sediment followed by organic matter accumulation

Answer

Tidal flows import suspended fine sediment that settles during slack water, and pioneer vegetation roots trap organics, driving rapid elevation gain.

Question 5

What is 'channel incision' and how does it impair ecosystem function in a restored stream?

Accepted Answer

Vertical downcutting that disconnects the stream from its floodplain and lowers the water table

Answer

Channel incision lowers the stream bed, disconnecting lateral floodplain access and dropping the riparian water table, degrading both aquatic and terrestrial habitat.

(CH) Certified Hydrographer Practice Test

(CH) Certified Hydrographer Practice Test

CH Ecosystem Restoration 3