D UK aquifers

Question 1

Mendips geology

Answer 1

series of periclines
Jurassic sediments have been eroded on the west side so limestone on west has been exposed to weathering for longer

Question 2

Karst hydrology features

Answer 2

sinking and gaining streams
network of caves, diffuse infiltration

Question 3

autogenic recharge

Answer 3

rain which falls on the limestone and immediately percolates
auto meaning self

Question 4

allogenic recharge

Answer 4

rain falls on impermeable rock and runs along surface till it reaches the permeable rock

Question 5

Limestone Mendips water pathway

Answer 5

down the bedding plain, up the joint

Question 6

Data quality and quantity

Answer 6

sparse & variable normally

Question 7

core data is biased towards

Answer 7

lithologies sufficiently consolidated to be sampled

Question 8

Sandstone

Answer 8

large pores- good storage
good core scale, limited scale dependence
affected by grain size variations and cementation

Question 9

Gouge

Answer 9

smear of clay or broken up rock (found in sandstones)

Question 10

lower greensand- found in surrey

Answer 10

intergranular flow, minor fracturing
ironstone hard bands locally impede vertical flow

Question 11

Permo-Triassic sandstone aquifer

Answer 11

large pores so drains easily
very high permeability
weakly cemented
good quality yield but in coastal areas seawater intrusion occurs

Question 12

Matrix properties controlled by

Answer 12

lithology and degree of cementation

Question 13

Permo-Triassic sandstone matrix

Answer 13

mostly isotropic
heterogeneity in K from inter-bedding of fine and coarser

Question 14

Permo-Triassic sandstone fracture flow

Answer 14

bedding plane fractures and inclined joints, solution enlarged fractures

Question 15

permeable faults shown as

Answer 15

recharge boundaries during a pumping test

Question 16

why are we so dependent on the chalk aquifers

Answer 16

high population
low rainfall and few site can be used for surface reservoirs

Question 16

composition of Chalk

Answer 16

fined grained
very high porosity but small pore size so limited permeability

Question 17

what dominates flow in Chalk aquifers

Answer 17

flow through disolusionally enlarged fractures and bedding planes

Question 18

vertical variations in Chalk

Answer 18

weathered at the surface that is more porous and permeable
as you go further into the saturated zone the amount of open fractures decreases

Question 19

Lateral variation in chalk

Answer 19

could be covered with glaciers or rock