Action D.14 Report on Nutrient Load

Transcription

1 WSTORE2 - LIFE11 ENV/IT/035 Reconciling agriculture with environment through a new water governance in coastal and saline areas Action D.14 Report on Nutrient Load VERSION DATE Modification Responsible Authors /01/2014 Prof Luca Palmeri L. Palmeri, G.M. Carrer, M. Bonato, A. Barausse 1

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3 Index TABLE OF CONTENTS Introduction 05 Sampling protocol 05 Results 07 Discussion 13 Attachemnts Sampling Sheet Database analysis Database Analysis a Monthly water outflow from the pumping station in Vallevecchia 18 04b Monthly nitrogen load discharged from the area 18 05a Monthly phosphorous load discharged from the area 19 05b Monthly total suspended solid load discharged from the area 19 3

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5 Introduction In the framework of the EU project LIFE+ WSTORE2, LASA (the Enviromentaml Systems Analysis Laboratory, Department of Industrial Engineering, University of Padova) is in charge of water monitoring through a monthly sampling campaign to assess water quality within the Vallevecchia system. Some monitoring activities in the area were also carried out from , thus well before the LIFE+ project start; the monitoring methods were improved and optimized over the past 10 years of activity building a large water quality database, which now represent a valuable baseline for comparing and interpreting the new data collected during WSTORE2. Within this report we highlight the results of our first year of activity in WSTORE2 (November 2012 November 2013), with a focus on nutrient loads discharged from Vallevecchia into the Northern Adriatic Sea, and also put it in relation to our long term water quality records to provide a comprehensive vision of the functioning of the Vallevecchia wetland system. Sampling protocol The monthly sampling activity was based on the collection of a one-litre bucket of water in three specific hydraulic nodes in the area: the pumping station, the gate and the storage basin. Here only data from the pumping station are reported because water flows (needed to calculate pollutant loads, i.e. mass fluxes, which are the focus of this report) could only be measured there. During each monitoring campaign, we also recorded (Attachment 01) chemical-physical parameters (temperature, conductivity, salinity, oxygen dissolved, ph) using a WTW multiline P4 measuring device and reported them on a field sheet. Water has been sampled monthly and analysed in our chemical laboratory to assess pollutant concentrations following standard methodologies (APAT/IRSA-CNR 2003; APHA/AWWA/WEF 2005). Concentrations have been determined for ammonia nitrogen (N-NH 4 ), oxidized nitrogen (N-NO X ), dissolved organic nitrogen (DON), particulate nitrogen (PN), total nitrogen (TN), orthophosphate phosphorus (P-PO 4 ), soluble unreactive phosphorus (SUP), particulate phosphorus (PP), total phosphorus (TP) and total suspended solids (TSS). To assess the loads outflowing from 5

6 the area into the Baseleghe Channel for nutrients and TSS, we have integrated concentration and water flows in the following manner. We have multiplied each given measured value of concentration C1 (see picture below) obtained from the laboratory analysis by the water volume outflowed from the pumping station between the sampling date for concentration C1 and that for the subsequently sampled concentration C2, to obtain the load discharged in the period between such sampling dates. The total annual load was simply the sum of such individual loads over the whole year. Figure 1 - Example of load assessment. Each sampled concentration was multipied by the total water volume outflowed from the system until the next sampling date. 6

7 Results The concentrations of the different nitrogen and phosphorus compounds provide us with important indications on the quality of water in the Vallevecchia basin, allowing us to understand how water quality and nutrient discharges to the eutrophic Northern Adriatic Sea are related to environmental and hydraulic conditions and to human activities taking place in Vallevecchia. In general, water quality can also provide indications about how the hydraulic functioning of the wetland affects salinity in the basin and how salt water can be contrasted, for example by storing freshwater inside the storage basin. Thus, water quality monitoring as foreseen in WSTORE2 is fundamental to set up integrated management plans of water resources in the area. To quantify the environmental impact of Vallevecchia on the neighbouring eutrophic Adriatic Sea, it is necessary to calculate the nutrients load discharged to the sea. The tables and the graphs below show monthly and annual water flows and discharged loads of nutrients from the pumping station during WSTORE2 activities and also over the preceding years. Table 1 Monthly water flow and nutrient load discharged from the pumping station during the first year of activity of the project (November 2012 November 2013). 7

8 Table 2 - Annual water flow and nutrient load flowed from the pumping station during all the past working activity of LASA in the Vallevecchia basin. The following graphs summarize rain inputs to the area, the water outflow, and nutrient loads discharged from , and also highlight the measurements made during the first year of the WSTORE2 project. 8

9 Figure 2 - Annual rain input and water outflow in Vallevecchia (referring to a surface of 592 ha) Figure 3 - Annual nitrogen load discharged from the area. 9

10 Figure 4 - Annual phosphorus load discharged from the area. Figure 5 - Total annual suspended solid load discharged from the area. 10

11 Figure 6 - Rain input and water outflow in Vallevecchia (referring to a surface of 592 ha) during the first year of the project Figure 7 - Nitrogen load discharged from the area during the first year of the project. 11

12 Figure 8 - Phosphorus load discharged from the area during the first year of the project Figure 9- Total suspended solid load during the first year of the project 12

13 Discussion As showed in the tables and in the graphs the first year of the project (November 2012 November 2013) was characterized by a great amount of rain input to Vallevecchia, above the seasonal mean and mainly concentrated in February and March. This has caused an increment in the water flowing from the pumping station and accordingly an associated increase of the nutrient loads of nitrogen, phosporus and total suspended solids emitted from the system. A key role in such an increase in nutrient emissions was played by the fact that the rain was concentrated during the months of February and March, a period that is usually used for agricultural practices (sowing and manuring). These practices were delayed due to rain and made in April, therefore in that month it was necessary to keep the field dry as much as possible to permit sowing and manuring, and water rich in nutrients was discharged from the area in April (as well as in February and March). Consequently the washout of the fields has caused high level of nutrients (P, N) outflowing from the Vallevecchia system. References o o APAT/IRSA-CNR 2003 Metodi Analitici per le Acque (Water Analysis Methods). APAT Manuali e linee guida 29/2003, Rome, Italy. APHA/AWWA/WEF 2005 Standard Methods for the Examination ofwater andwastewater, 21st edition. APHA/AWWA/WEF, Washington, DC, USA. 13

14 Attachments 14

15 Attachment 01 Sampling Sheet 15

16 Attachment 02 Database

17 Attachment 03 Database

18 Attachment 04 4a- Monthly water outflow from the pumping station in Vallevecchia. 4b - Monthly nitrogen load discharged from the area. 18

19 Attachment 05 5a - Monthly phosphorus load discharged from the area 5b - Monthly total suspended solid load discharged from the area. 19