Monitoring Tasman's Estuaries - why, how and where

Why Monitor Our Estuaries

To ensure the community and ecological values of our estuaries are maintained or enhanced, we have to know what state (condition) they are in. The specific aims of Council's estuary monitoring programme are to:

  • assess the condition and trend of the health of our estuaries
  • to determine the likely impact of various activities or stressors that affect the condition of our estuaries.

How Council Monitors Estuaries

The monitoring programme is made up of four components:

Fine scale assessments of physical, chemical and biological components of estuarine sediments in the mid-intertidal zone and broad-scale mapping of vegetation types and substrate use methods generally in accordance to the National Estuary Monitoring Protocol.  

Sediment accumulation rates are assessed by measuring from the surface of the estuary down to plates buried about 300mm below the surface. This is carried out annually. 

Broadscale habitat mapping provides an historical perspective, from analysis of high quality aerial photographs dating from as far back as the 1940s. This assessment uses methods generally in accordance to the National Estuary Monitoring Protocol.

Vulnerability assessments aim to predict how various land-use stressors effect the values of a particular estuary. These assessments are carried out using methodology adapted from UNESCO (2000). 

Water quality assessments involve sampling enterococci and temperature on an almost-weekly basis from Late November to early March every second year for the purpose of determining the health of the estuary for swimming. This monitoring follows the Microbiological Water Quality Guidelines 2003.

Where Council Monitors Estuaries

Since 2002 Council has undertaken assessments of five major estuaries or embayments vulnerable to human-landuse pressure. These estuaries include (show on a map):

  • Waimea (hyperlink to each of these estuaries)
  • Moutere
  • Motueka delta
  • Motupipi
  • Ruataniwha

Only one sampling event has been undertaken at each of these estuaries except for the Waimea (two sampling events). We plan to repeat this monitoring on a six-yearly cycle once we have completed vulnerability assessments and synoptic surveys of all the remaining unmonitored estuaries and embayments that have some risk of human disturbance (ie not with catchments entirely within national parks). We hope to finish these vulnerability assessments and synoptic surveys by 2012.