GDTE site Kazu Leja:conceptual model

University of Latvia

Andis Kalvāns, Jānis Bikše, Konrāds Popovs

Nature Conservation Agency, Latvia

Agnese Priede

Conceptual model workflow

Three step process suggested but not mandatory

• Step 1, basic CM for the groundwater body• 1a, qualitative CM• 1b, Quantification of parameters in

the CM

• Step 2, to include risk assessment aspects into the CM• 2a, qualitative description of impacts

(anthropogenic)• 2b, quantitative description of

impacts

• Step 3, to include risk management aspects into the CM• 3a, description of effects of existing

measures• 3b, prediction of effects of existing

and future measures

Step 0: Why Kazu Leja is an important GDTE site?

Location of Kazu Leja

Similar to the borders of Kazu ieleja Nature Monument (protected nature

area of national importance, overlapping with Gauja National Park – Natura

2000 site)

Identified GDTE in Kazu Leja

◆ Petrifying springs with tufa formation:

- wet patches around spring discharges on slopes

- spring waterfalls

◆drained mesic to wet fen grassland on peat soil on the bottom

of the valley

Particular species – what we know for sure (but

maybe there are more)

Rare, protected plant species

Cypripedium

calceolus

In this area, on

slope, not

related to

GDTEs.

Several other

orchids

Largely related

to GDTEs (but

not all of them).

Primula

farinosa

Largely related

to GDTEs

(calcareous

fens).

Stellaria

crassifolia

Largely related

to GDTEs

(spring mires).

Gymnocarpiu

m robertianum

On tufa cliffs

and calcareous

rocky slopes.

Not related to

GDTEs.

Habitats – petrifying springs with tufa formation

Habitats – petrifying springs with tufa formation

Habitats – petrifying springs with tufa formation

Habitats – ponds, pits, fen grassland,

carbonatic rocky slope, slope forests

Habitats – ponds, pits, fen grassland,

carbonatic rocky slope, slope forests

Step 1: Basic conceptual model for groundwater body

Step 1: Conceptual model Kazu Leja

Questions

• The role of the groundwater in Kazu Leja site• What aquifers are feeding the

Kazu Leja site?

• What is the proportion of precipitation, surface runoff and groundwater in the water budget?

• Is there certain traits of water composition particularly important for the biota?

Qualitative conceptual model

• Hydrology

• Geology

• Hydrogeology

• Precipitation and evapotranspiration

• Groundwater discharge• D3pl

• D3am

• D3gj

• Surface catchment

• Groundwater recharge

Catchment area for Kazu Leja site

• Delineated based on digital elevation model (DEM)

• Catchment area 4.7 km2

• Includes agricultural lands, drainage system

Conceptual geological cross-section

D3gj

D2br

D2ar

D3amD3pl

Q3

Close-up for conceptual geological cross-section

1. The valuable GDTE site:Petrifying springs with tufa formation

2. suggested groundwater discharge at the base of the valley, drained mesic to wet fen grassland on peat soil

Quantification of parameters in the CM

• Groundwater table in aquifers• hydrogeological models of

Latvia (PUMA and LAMO)

• Water abstraction sites

= Downward gradient

Step 2: Risk assessment

Step 2: risk assessment

description of impacts

• Spring water interception by individual households

• Distant groundwater extraction: Cēsis, Priekuļi, Jāņmuiža

• Abandoned dolomite quarry near Cēsis

• Land drainage system: flow capture and/or nutrient runoff

• Nutrient and pesticide runoff from intensive farmland

Risk assessment – quantitative description of impacts• Groundwater abstraction

• Spring «interception» by locals

• Dolomite mining (abandoned quarry)

• ??

?

Risk assessment – quantitative description of impacts• Drainage system

• Agriculture - nutrient and pesticide runoff

Step 3: Risk management

Existing risk management measures

Triple-Protected area

• Gauja National Park

• Nature reserve territory

• Geological nature monument

• E.g. Mining not allowed except groundwater for personal usage

• Hydrotechnical infrastructure is not allowed

Next step: Data acquisition

Groundwater monitoring wells

• Groundwater wells:• Level

• Flow direction

• Temperature

• Chemistry

• Stable isotopes

• Development of low cost sensors:• Precise groundwater hydraulic head

measurements

• Temperature measurements at many places

Environment variables

+ Stable isotopes in:• Surface water;

• Soil water;

• Rain water;

• Plant leaves

• Remote sensing with drone in visible and infrared spectrum

• Field survey

• Geophysics?

Field survey:(ground) water mineralization and temperature

Thank you!