Submission in Support of Water Conservation Order By Klaus Thoma Soil Scientist 347 East Takaka Rd RD1 Takaka, 7183

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1 Submission in Support of Water Conservation Order By Klaus Thoma Soil Scientist 347 East Takaka Rd RD1 Takaka, 7183 Background I have practiced in my field of expertise, soil science and water quality management, since 1981 in my capacity as research officer with the then South Australian Department of Agriculture and since 1993 in Golden Bay. Most relevant for this submission is research into water quality effects by intensive pastoral land use in the Motupipi catchment with TDC as client and the development and oversight and management of the then NZMP s Takaka milk factory s wastewater discharge consents. I hold academic qualifications, both from overseas and New Zealand, in my fields of expertise in soil science, water quality management, political science and political economy. In my submission I will aim to contribute in my fields of expertise, soil science and water quality management which I practiced in various projects in Golden Bay since I support the Te Waikoropupu Springs Conservation Order (WCO) 2015 as outlined in schedule 1 and 2 (Outstanding characteristics or features). I support the provisions and restrictions sought under Section C, n particular C1-82.g to C1-82.n. In my submission I would like to provide some evidence that: 1) the unconfined aquifer in conjunction with the high rainfall regime provides a pollutant leaching pathway into the Mt Arthur Marble aquifer; and 2) current intensive pastoral land use provides sediment, microbiological contamination and nutrients to the recharge drainage into the Mt Arthur Marble aquifer. I hope that my contribution provides some practical solutions towards contemporary and sustainable land use practices and therefore ensure that the exceptional, physical, spiritual and natural qualities of the Te Waikoropupu springs are maintained.

2 I wish to be heard in future submission proceedings. Upgradient/upstream Land Use Practices Affecting Te Waikoropupu Springs Dairying is an important land use in the Takaka Valley upstream/upgradient of Te Waikoropupu Springs. The majority of dairy farms are located on the floodplains of the Takaka River catchment and a series of higher terraces. A large portion of dairying is also located on the unconfined section of the Mt Arthur marble aquifer which recharges the Te Waikoropupu Springs. The unconfined nature of the geology can also be seen by a series of sinkholes extending up the Takaka valley. These sink holes provide clear evidence of direct connection to the Mt Arthur aquifer. Soil types also pose a risk for nutrient leaching into the unconfined Mt Arthur aquifer. The soil types of the Bainham Formation (In1/In2) consist of almost unweathered, round gravel with stone content of top soils reaching up to 85% of the soil matrix (Thoma Consulting 1997; Soil Bureau 1968). Dairy farms in a large part of the Takaka valley are part of this geology. Consequently nutrient absorption and water holding capacity of these soils is very limited and is particularly challenging when irrigation and/or unpredictable rainfall events (~2500 mm annual rainfall) push wetting fronts beyond the pasture root zone. During intensive rainfall periods and in particular during winter months these pastoral soils maintain soil moistures at field capacity. Fertilizers, particularly nitrates and sediment are easily entrained into the subsurface leaching processes. Lower Terraces are mainly formed on recent flood plain Karamea soils which drain into the Takaka River with its connection to the unconfined Mt Arthur aquifer and/or via sinkholes. Again the low lying nature of these recent alluvial soils exposes them to subsurface/surface drainage during long periods of high soil moisture contents. Thus, soil types, topography, the high rainfall regime and the unconfined nature of the Mt Arthur aquifer pose a high risk for nutrient leaching into ground water. Nutrient Inputs There is no reliable data on fertiliser use in the Tasman District. Fertilizer use is a permitted activity and any fertiliser management relies entirely on unenforceable TDC application guidelines and industry practice recommendations.

3 There is some anecdotal evidence to suggest that urea (nitrogen) fertilizer applications of the order of 400 to 500 kg/ha/annum on dairy pasture are common practice. Although there are best practice guidelines promoted by industry bodies as well as Tasman District Council, the actual fertilizer application rates and its leaching process are neither transparent nor well understood in quantitative terms. Current Water Quality Monitoring Surface water quality of the Takaka River catchment is monitored by Tasman District Council s (TDC) State of the Environment (SoE) program (James, T and McCallum, J 2015). The sampling regime, however, is restricted (there are several reasons also financial) to monthly sampling during base flow conditions. The most relevant sampling site (from the Takaka river) for the Te Waikoropupū Springs is sampled at Kotinga bridge near the township of Takaka. There is scientific consensus that flood conditions nearly always show higher sediment and nutrient loadings than during base flow conditions. This dynamic applies particularly when intensive agricultural land uses are located upstream. In the case of the Takaka Valley catchments, there is little data on water quality dynamics during flood events but what information exists from the Takaka River, Fish Ck., Aaron Ck. and the Motupipi catchment confirms significantly higher loadings of nutrients and sediment compared to base flow conditions (Thoma, K 1997 and 1998, Friends of Golden Bay 2018 unplublished data). Data from the Te Waikoropupū Springs and Kotinga Bridge sampling loactions show an increase of nitrate concentrations over time reaching threshold concentrations a for the Te Waikoropupu main springs site according to NIWA. The exclusion from analysis, however, of a large pollutant pathway with a direct access to the unconfined aquifer and the omission of runoff event sampling ignores a potentially highly significant nutrient pathway to the Te Waikoropupu springs.. Conclusions Pastoral land use in the high rainfall regions of the Takaka River catchment is located above the unconfined sections of the Mt Arthur aquifer which recharges the Te Waikoropupu Springs. Several soil types, particularly those formed on the Bainham Formation have a very limited nutrient holding as well as high drainage capacity into the unconfined Mt Arthur aquifer providing a significant pollutant entry point into the Te Waikorupupu Springs recharge field.

4 Nitrate concentrations in the Te Waikaropupu Springs are reaching nutrient threshold levels according to NIWA. TDC s State of the Environment River Water Quality program is not designed to monitor full nutrient loading dynamics because of lack of event sampling which is crucial for establishing nutrient losses from the Takaka catchment.. Surface water of the Takaka River sampled at Kotinga bridge also point to increases in nitrate concentrations during base flow conditions. The lower nitrate concentration samples at Kotinga Bridge (median 0.16 ppm), however, are at odds with the increasing trend in nitrate concentrations at Pupu main springs (median 0.38 ppm) (Daughney, C.; Randall, M. 2009). One needs to conclude that the current sampling program, being based on base flow sampling conditions, is under estimating total nitrate exports from farm land and that nitrates enter the Mt Arthur marble aquifer most likely via the unconfined aquifer areas of the Takaka Valley. Thus, current land use practices, the high rainfall regime and the location of these practices above the unconfined Mt Arthur aquifer suggest a direct pathway for fertilizer residues, sediment and biological contamination into the Te Waikoropupu Springs recharge field. This information is crucial for the development of appropriate land use practices under the high rainfall conditions of Golden Bay. Recommendations Add event sampling, at least at Kotinga bridge, to TDC s State of the Environment program; Change the permitted use status of fertilizer applications to a controlled activity status; Analyse land use practices, particularly during high rainfall periods with a view to reduce pollutant loadings. References Daughney, C.; Randall, M National Groundwater Quality Indicators Update: State and Trends , GNS Science Consultancy Report 2009/ p. Prepared for Ministry for the Environment, Wellington, New Zealand. Spreadsheet 1 available at James, T and McCallum, J State of the Environment Report: River Water Quality in Tasman District Prepared for Tasman District Council.

5 Soil Bureau (1968). Soil Burau Bulletin 27. General Survey of the Soils of South Island, New Zealand. New Zealand Department of Scientific and Industrial Research. Thoma, K. (1997). Land use and geology in the Motupipi catchment. Prepared for Tasman District Council. Thoma Consulting (1997). Investigation of Soils and Hydro-Geology of Land Disposal Sites for Whey and Washdown Mixtures. In: Wastewater Discharge Consent supplementary information. TDC. Thoma,K. (1998). Preliminary Investigation of Land Use Effects on Takaka River Water Quality during Flooding Events. Prepared for Tasman District Council.