Catchment Impacts on Hydrology & Water Quality Graphics - - PowerPoint PPT Presentation

Te Waikoropupū Catchment Impacts on Hydrology & Water Quality

Graphics accompanying summary evidence of Andrew Fenemor for Tasman District Council

A p r i l 1 8 T I T L E G O E S H E R E P A G E 2

Hydrology

Flow Modelling Compartments for the AMA

3

TDC groundwater records, Takaka Valley, 1981-2015

4

5,000 10,000 15,000 20,000 25,000 30,000 35,000 40,000 45,000 50,000 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 GW level elevation (mm amsl) Date (1 Jan yyyy)

Takaka Groundwater Levels

Takaka Fire 2 (23648) TDC Office (6339) Pupu Main Spring (6013) Savage (6713) Sowman (6912) Takaka Firestation (6535) Cserney (6418) Jefferson (6829) Hamama (6710) Motupipi SubStn (6413) Ball (6011) Bennett (6815) Grove Orchard (6224) Motupipi Substation Cserney Ball Pupu main spring TDC offices Firestation Hamama Sowman Jefferson Savage Bennett Grove Orchard

Modelled and measured flows, Te Waikoropupū Springs, 1999-2015

5

2 4 6 8 10 12 14 16 18 20 22 24 1999 2001 2003 2005 2007 2009 2011 2013 2015 Groundwater discharge (m3/s) Year

AMA Groundwater Discharge

Springs River (Main Spring + Fish Creek - Salmon Farm) Modelled Measured

Modelled periods when Takaka River was dry, 2010-2014: blue = fully flowing; white = partly dry

6

1 Jun-10 Jun-11 Jun-12 Jun-13 Jun-14 Date (1 Jan yyyy)

Prediction of Full-Length Flow in the Takaka River

~ 170 days ~ 180 days ~ 190 days Partial-length flow days per year ~ 90 days (to 31 Dec '14) ~ 160 days

Relative AMA recharge from rainfall vs river leakage, 1980-2015

7

4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 Recharge (m3/s) Date (1/1/yyyy)

Average Groundwater Recharge

(Exponentially Weighted Moving Average) Land surface recharge Average land surface recharge River recharge Average river recharge

Changes in flows from Te Waikoropupū Springs for 4 land use scenarios

Modelled flow statistics for various scenarios for the period 1990-2014 (unless otherwise stated) River Measured Current State (Calibration) No Consumptive Water Takes Scenario Double Current Irrigation Scenario Hypothetical Current Scenario WITHOUT Cobb Dam No Development Scenario Average (l/s) Main Spring 9,910

(synthesised by TDC)

9,740 9,910 9,560 8,890 8,480 Fish Creek 3,390 3,060 3,110 3,000 2,810 2,470 7-day MALF (l/s) Main Spring 7,290

(synthesised by TDC)

7,250 7,490 7,010 6,320 5,950 Fish Creek 570 530 640 430 290 230 Zero-flow days (average/year) Main Spring

(synthesised by TDC)

Fish Creek 1 3 6 6 1 in 10 year low flow (l/s) (2009/10 season) (approximate) Main Spring 5,985

(synthesised by TDC)

6,110 6,370 5,850 5,320 5,050 Fish Creek 35 65 180 45 45 10

8

9

Water Quality (Nitrate-Nitrogen)

Groundwater Nitrate by Water Body 2006-2016 (from J Thomas evidence Fig 14)

1 0

River nitrate-nitrogen concentrations for Takaka River at Harwood’s and Kotinga

2 6 A p r i l 2 0 1 8 F e n e m o r S u m m ar y - G r ap h i c s 1 1

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 1984 1988 1992 1996 2000 2004 2008 2012 Nitrate-nitrogen concentration (g/m3) Date (1 Jan yyyy)

Surface Water Nitrate-Nitrogen Concentrations

Harwood Kotinga

Soil water holding capacity red and orange are more gravelly so hold less water before they ‘leak’ Unmapped = hill country (low WHC; 40 mm assumed)

Current and proposed (waiting list – in pink) irrigation water permits Irrigation scenarios modelled

1 3

Irrigation Scenario in the AMA Recharge Zone Ha irrigated dairy Ha dryland dairy

Current State 993 2063 Current+Proposed Irrigation 1462 1594 Current +Proposed+Plausible 2045 1011 Current+Proposed+Plausible+Unlikely 3056 766 l/sec AMA recharge zone water take allocation limit (one of the FLAG options) 1544 1512 Double current irrigation 1986 1070 100% dryland dairy 3056 No Development - AMA recharge zone

Modelled nitrate from Te Waikoropupū Springs for 7 land use scenarios

1 4

No development (AMA recharge zone) 100% dryland dairy Current Dairy Current+ Proposed 766 l/sec allocation limit from FLAG Double current irrigation Current +Proposed+ Plausible Current+Proposed+ Plausible+Unlikely 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 500 1,000 1,500 2,000 2,500 3,000 3,500 Nitrate-nitrogen concentratin (g/m3) Irrigated area in AMA recharge zone (ha)

Nitrate-Nitrogen Concentrations

Main Spring Fish Creek AMA aquifer

Scenario Calculated AMA Fully Mixed Nitrate Concentrations (g/m3) Current Dairy 0.41 Current+Proposed 0.44 Current +Proposed+Plausible 0.47 Current+Proposed+Plausible+Unlikely 0.54 766 l/sec upper allocation limit from FLAG deliberations 0.44 Double current irrigation 0.47 100% dryland dairy 0.35 No Development - AMA recharge zone 0.002

Modelling Assumptions & Uncertainties

• Water in = water out (water balance)
• Nitrate in = nitrate out (no attenuation)
• Nitrate fully mixed with flow reaching Te

Waikoropupū

• Marble aquifer ‘plumbing’ water balance

consistent with Stewart & Thomas (2008)

• Dairy farm N-leaching rates from

OVERSEER™ ver 6.1.2; rates for other land uses from literature