The Yaoundé 2^nd supply dam water, located in Nkolbisson-Minkoameyos village is exposed to demographic pressure. Indeed, the lake is contaminated by all kinds of domestic waste directly disposed on the rivers upstream from supply dam water or brought by runoff and floods in the rainy seasons. The main interest of Minkoameyos’ Lake is that it is the largest and least exposed hitherto of well-known public Lakes that hosts Yaoundé city (e.g., Ngoa-Ekelle, Minkoameyos, Atemengue, Melen, Obili, Olezoa, Oyomabang, Emana, and Municipal Lake). Abandoned for years, this lake in the past supply water to Yaoundé populations and it is now experiencing a resurgence of interest [1] - [5] provided by the rehabilitation project launched since August 2011 by CAMWATER Company. To reassure consumers of water supplied by Minkoameyos Lake, it is important to organize more often, campaigns on physicochemical and bacteriological analyzes of water samples from surface to desired depths of the lake. Confidence necessary to safeguard the mutual interests of CDE-CAMWATER Companies (companies in charge with drinking water management) and consumers can thus be established and strengthened at the same time. Everyone knows that, in a fluid (liquid or gas) at rest, the isobars are horizontal surface. This fluid dynamic balance theorem provides a familiar communicating containers’ principle which statement is: surfaces of both communicating containers’ liquid at rest in contact with the atmosphere also at rest are in the same horizontal plane. Those above and very useful hydrodynamics theorem and principle have many industrial applications such as vertical alignment of the walls in houses’ building, horizontal alignment of bridge or providing drinking water to each house in town. We deal in this paper, with an adequate and effective way of exploiting the communicating containers’ principle. Our work formally consists on providing water samples from desired depths of Nkolbisson Lake. A designed tube for this purpose named Mbane Bathymetric Tube (MBT) has been conceived and built in order to improve the tools and techniques for water quality interpretation. Our experience in Nkolbisson Lake is an adequate advance for drinking water managerial techniques because it allows an appropriate peer treatment of contaminated water which quality interpretation is irrefutable. Finding out more about the causes of the disease must be a prerequisite before looking for appropriate treatment of that disease (in our case: Finding out more about wastewater physicochemical and bacteriological interpretation is a great challenge before acquiring adequate treatment station).

Everyone must learn a little more about communicating container’s principle which is valid only when both liquid and atmosphere are at rest.

The Yaoundé 2^nd dam water retention or lake, located in Yaoundé neighborhoods (Nkolbisson-Minkoameyos village in this case (Figure 7)) is exposed to demographic pressure. For this reason, this lake is contaminated by all kinds of domestic waste directly disposed on the rivers upstream from lake or brought by runoff and floods in the rainy seasons. The main interest of Minkoameyos’ Lake is that it is the largest and least exposed hitherto of well-known public lakes that hosts Yaoundé city (e.g., Ngoa-Ekelle, Minkoameyos, Atemengue, Melen, Obili, Olezoa, Oyomabang, Emana, and Municipal Lake). Abandoned for years, this lake in the past supply water to Yaoundé populations and it is now experiencing a resurgence of interest provided by the rehabilitation project launched since August 2011 by CAMWATER Company. To reassure consumers of water supplied by Minkoameyos Lake, it is important to organize more often, campaigns on physicochemical and bacteriological analyzes of water samples from surface to desired depths of the lake. Indeed, finding out more about wastewaters bacterial or chemical pollution before equipping (or acquiring) water treatment station is now possible with our MBT for unlimited desired depths.

Our campaigns (Figure 8) on physicochemical and bacteriological analyzes of water samples coming from surface to desired depths of the Yaoundé 2^nd supply dam was performed on July 03, 2014. Our difficulty was the lack of financial support mainly for physicochemical and bacteriological analyzes fees. Indeed, we were not able

to analyze more than 09 water samples. That is why only 03 database pointes (DBP) has been choice as shown on Figure 9.

Table 1 contains analysis results of various wastewater samples coming from different desired depths (0 meter, 1 meter, 2 meters) of the Yaoundé 2^nd supply dam. The results in Table 1 show that levies on the water surface provide false or incomplete information on the quality of deep layers of the dam. Matters known as suspension one are also find in 1 meter deep as well as 2 meters. Moreover, nothing prevents suspension matters to exist inside 6 - 7 or 8 meters layers. One should talk about immersion matters: which perfectly corresponds to Thermodynamics or Physics perception of the concept of density of a body. Histograms on the suspended matters’ concentration and pH values of wastewater at various desired depths are presented in Figures 10(a)-(d) and Figure 11.

Immerging Matters = IMM; Total Dissolved Solid = TDS; Fecal Coliforms = FC; Electrical Conductivity = C_nd.

In a fluid (liquid or gas) at rest, the isobars are horizontal surface. This fluid dynamic balance theorem provides adequate advance to tools and techniques for Water Quality Interpretation. We have deal in this manuscript with an effective way of exploiting the familiar communicating containers’ principle. That formally consists on providing water samples from desired depths of rivers, oceans, retention dams, etc. as shown on Table 1 and related histograms (Figure 10) and Figure 11.

The aim of our study was to provide a new tool to conventional protocols (i.e., Tools and Techniques) developed for the collection of water samples. All protocols known today, did not allow to go down more than 30 centimeters in depth without the risk of contamination of water samples when they are bring to the surface. Due to lack of financial support, the team who did the taking of water samples was forced to move on tree trunks as presented in Figure 8(a) and Figure 8(b). We were able to perform many other samples to ensure a wider coverage of the lake. But this would have been useless for the simple reason that the laboratory tests are expensive. The effectiveness of the MBT, however, was demonstrated in this experiment. The MBT-protocol will allow the authorities responsible for the management of drinking water resources in Cameroon, to better equip the Camwater wastewaters treatment stations. More adequate measures campaigns will help to identify potential exogenous (and endogenous) contaminating sources of the dam and to eradicate them. We are considering very carefully the modeling of the physicochemical and biological evolution of the basin pollutants in order to allow (with appropriate applications) the site to be under the satellites surveillance. This approach will allow to remotely controlling the level of contamination of this strategic site.