\begin{table}%t4
\caption{Mean intensities of the first rotational transitions of ortho and para~\element{H_{2}O} (in ${\rm erg~cm^{-2}~s^{-1}~sr^{-1}}$) and (last column) optical depth at line centre for model~PDR-c.}
\label{table_intensites}
%\centering
\small
\begin{tabular}{l l l l l l l l}
\hline \hline
Transition & $\lambda_{\rm ul} {\rm (\mu m)}$ & PS05 & PDR-a & PDR-b1 & PDR-b2 & PDR-c & $\tau_{\rm c}$\\
\hline
&&&&&&& \\[-8pt]
$o{-}\element{H_{2}O}~ 1_{10}\rightarrow1_{01}$ & 538.2 & $ 4.00\times 10^{-8}$  & $2.16\times 10^{-8}$    & $2.58\times 10^{-8}$ & $3.30\times 10^{-8}$  & $3.58\times 10^{-8}$ & $429$ \\
$o{-}\element{H_{2}O}~ 2_{12}\rightarrow1_{01}$ & 179.5 & $ 5.66\times 10^{-7}$   & $1.03\times 10^{-9}$    & $1.00\times 10^{-7}$ & $9.84\times 10^{-7}$  & $8.69\times 10^{-7}$ & $430$ \\
$o{-}\element{H_{2}O}~ 2_{21}\rightarrow1_{10}$ & 108.1 & $ 8.26\times 10^{-10}$ & $1.14\times 10^{-13}$  & $2.47\times 10^{-8}$ & $4.18\times 10^{-7}$  & $7.04\times 10^{-7}$ & $0.97$ \\
$o{-}\element{H_{2}O}~ 2_{21}\rightarrow2_{12}$ & 180.5 & $ 5.90\times 10^{-11}$ & $9.40\times 10^{-15}$  & $2.24\times 10^{-9}$ & $3.61\times 10^{-8}$  & $6.50\times 10^{-8}$ & $0.12$ \\
$o{-}\element{H_{2}O}~ 3_{03}\rightarrow2_{12}$ & 174.6 & $ 5.70\times 10^{-10}$ & $1.80\times 10^{-13}$  & $5.01\times 10^{-10}$ & $4.73\times 10^{-8}$  & $1.22\times 10^{-7}$ & $0.24$ \\
$o{-}\element{H_{2}O}~ 3_{12}\rightarrow2_{21}$ & 260.0 & $ 1.86\times 10^{-12}$ & $1.24\times 10^{-15}$  & $6.15\times 10^{-13}$ & $1.55\times 10^{-10}$ & $4.56\times 10^{-10}$ & $2.6\times10^{-3}$ \\
$o{-}\element{H_{2}O}~ 3_{12}\rightarrow3_{03}$ & 273.2 & $ 1.11\times 10^{-11}$ & $7.27\times 10^{-15}$  & $3.62\times 10^{-12}$ & $9.13\times 10^{-10}$ & $2.68\times 10^{-9}$ & $2.5\times 10^{-3}$ \\
\hline
&&&&&&& \\[-8pt]
$p{-}\element{H_{2}O}~ 1_{11}\rightarrow0_{00}$ & 269.3 & $ 1.76\times 10^{-7}$   & $9.88\times 10^{-9}$   & $5.37\times 10^{-8}$ & $2.96\times 10^{-7}$ & $2.64\times 10^{-7}$ & $1672$ \\
$p{-}\element{H_{2}O}~ 2_{02}\rightarrow1_{11}$ & 303.4 & $ 1.78\times 10^{-9}$   & $7.75\times 10^{-11}$ & $1.68\times 10^{-9}$ & $4.25\times 10^{-8}$ & $9.75\times 10^{-8}$ & $1.13$ \\
$p{-}\element{H_{2}O}~ 2_{20}\rightarrow1_{11}$ & 101.0 & $ 1.93\times 10^{-10}$ & $1.34\times 10^{-14}$ & $9.66\times 10^{-9}$ & $5.24\times 10^{-7}$ & $9.37\times 10^{-7}$ & $1.88$ \\
$p{-}\element{H_{2}O}~ 2_{11}\rightarrow2_{02}$ & 398.6 & $ 3.34\times 10^{-11}$ & $1.64\times 10^{-13}$ & $1.92\times 10^{-10}$ & $1.26\times 10^{-8}$ & $2.88\times 10^{-8}$ & $2.9\times 10^{-3}$ \\
\hline
\end{tabular}
\end{table}