## 3 Results and Discussion
### Optimization of the W2 WQMP - Results and Discussion  
After the data validation and integration process, it was much easier to gain an overview of the W2 WQMP datasets and make choices concerning the optimization processes. For this WQMP, \begin{table}
\begin{tabular}{p{142.3 pt} p{142.3 pt}} \hline \hline
**Actionable Tasks** & **Verifications that Must be Made Prior to the Final Decision** \\ \hline Verify whether changes in physicochemical parameters and other observations made in the river WQMP of this watershed can have an effect on the structure of the cyanobacteria community of Lake Saint-Charles & The watershed of Lac Saint-Charles is exposed to multiple stressors. Data from the river WOMP show that specific conductivity is raising constantly in the main inflows of Lac Saint-Charles (APEL 2015; APEL 2016). Therefore, changes in the cyanobacteria community may occur rapidly and be an indicator of these changes. Further analysis is necessary to identify whether these changes can also be documented in Lac Saint-Charles before drastically reducing the sampling frequency. \\ Verify sampling strategy & If there are no changes, the six years of intensive cyanobacteria monitoring can be taken as a reference, and the sampling frequency can be reduced (e.g., every 4 weeks). \\ Verify sampling strategy & If changes in the lake occur, the sampling frequency can be increased again. \\ Verify which station can be retrieved between C01 and SC0 & Since no difference was observed between those two stations, select the station which requires less effort to be sampled. Since SC0 is accessible from the shore, this station should be kept and C01 eliminated. \\ \hline Verify whether changes in the cyanobacteria monitoring affect other monitoring objectives & During the process of understanding the rationale of the WQMP in the W1 watershed, many other monitoring objectives were identified for this lake. For any drastic change in the current strategy, the incidence on the other objectives must be evaluated. These objectives can be retrieved from the database, and the IDSS proposes the validation questions accordingly. \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Summary of the actionable tasks to take final decisions for the optimization of the W1 WQMP. from 2328 sample contexts (sampling outings) taken on 66 stations, a maximum of 14 water quality parameters could be observed and field observations would include precipitation classes and ambient temperature. However, only for TSS, TP, FC and precipitation classes were sufficiently consistent data sets available for all these stations. The proportions of non-available data (NA) were only 6.4% (TSS), 7.2% (FC), and 18.4% (TP) respectively. The missing information on precipitation classes which could not be retraced represented 12.8%. Following validation with the WQMP managers, the optimization was conducted on these parameters and on all stations. The missing data were reconstructed with the package MissMDA with Software R--for further information consult [PERSON] et al. [32] and [PERSON] [33]. The optimizations procedures proposed by [PERSON] et al. (2012) and [PERSON] et al. (2014) were then applied to these data sets. For the W2 WQMP, the results on the optimization question, verify whether a reduction of the number of sampling sites is possible based on criteria such as redundancy of information between sampling sites, are illustrated in Figure 10A. Figure 10B illustrates the sampling site network after having applied the first series of questions, as discussed in Section 2.5. The results of this step suggest that four of the seven stations proposed for removal by the Kriging analysis could indeed be removed: stations 35, RDN121, 04010191, and 0401010192. For stations 21 and RDN121, information between the upstream and downstream stations was sufficient to obtain a picture on water quality, making these section stations unnecessary. Stations 04010191, and 0401010192 are tributaries to a lake and do not contribute any information to the river sampling site network.