# connecting arrows between vertical and curved line

I would like to make a few alterations to the following figure:

\documentclass[12pt]{article}
\usepackage{tikz}
\usetikzlibrary{snakes,arrows}

\begin{document}
\begin{tikzpicture}
% draw the ground
\draw (0,0) -- (8.5,0) .. controls (8.5,-1) and (10,-1).. (11,-1) -- (14,-1);
% draw lake surface
\draw [snake = snake,segment amplitude =.4mm, segment length = 5mm] (8.5,0) -- (14,0);
% draw the wind velocity field
\draw[very thick,gray](12,0)--(12,5);
\draw (12,0)..controls(12.5,2) and(14,3) ..(14,5);% draw profile
\end{tikzpicture}
\end{document}


From this figure I would like to add horizontal arrow lines from the straight vertical line to the curved line. My attempt:

\documentclass[12pt]{article}
\usepackage{tikz}
\usetikzlibrary{snakes,arrows}

\begin{document}
\begin{tikzpicture}
% draw the ground
\draw (0,0) -- (8.5,0) .. controls (8.5,-1) and (10,-1).. (11,-1) -- (14,-1);
% draw lake surface
\draw [snake = snake,segment amplitude =.4mm, segment length = 5mm] (8.5,0) -- (14,0);
% draw the wind velocity field
\draw[very thick,gray](12,0)--(12,5);
\draw (12,0)..controls(12.5,2) and(14,3) ..(14,5);% draw profile
\foreach \y in {2,3,5}
\foreach \x in {12.5,14,14}{
\draw[=>stealth,->](12,\y)--(\x,\y);
}
\end{tikzpicture}
\end{document}


which is obviously incorrect, but I cant seem to solve this. Also, how could I make the horizontal lines be drawn 5 time evenly spaced vertically?

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The snakes library is deprecated, use the decorations.pathmorphing library instead.

To find the right points on the curved line I have used the intersections library.
The curved line is named curve.

In a loop that iterates over \y from 1 to 5 a path is named horizontal that goes from (12, \y) to (15, \y) (so that it crosses the curved path). The intersection of curve and horizontal is named intersection-1 and is used in a drawn path.

## Code

\documentclass[12pt]{article}
\usepackage{tikz}
\usetikzlibrary{decorations.pathmorphing,arrows,intersections}

\begin{document}
\begin{tikzpicture}
% draw the ground
\draw (0,0) -- (8.5,0) .. controls (8.5,-1) and (10,-1).. (11,-1) -- (14,-1);
% draw lake surface
\draw [decorate, decoration={snake,amplitude =.4mm, segment length = 5mm}] (8.5,0) -- (14,0);
% draw the wind velocity field
\draw[very thick,gray](12,0)--(12,5);
\draw[name path=curve] (12,0)..controls(12.5,2) and(14,3) ..(14,5);% draw profile
\foreach \y in {1,...,5}{
\path[name path=horizontal] (12,\y) -- + (3,0);
\draw[-stealth,name intersections={of=curve and horizontal}] (12,\y) -- (intersection-1);
}
\end{tikzpicture}
\end{document}


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