When it finally rains, it really pours in this country. Our all-too-arid landscape is often inundated with downpours so heavy that runoffs cause flooding in low-lying locations such as the Sharon, southern Tel Aviv, Haifa's bayside suburbs and Nahariya. What makes each of these locales prone to flooding isn't always identical, but the man-made factor is present in all cases. The annual destruction of property (and sometimes loss of life, as in Jaffa a few years ago) is eminently preventable. The authorities know what they need to do. The problem is that each year they are "surprised" anew by the advent of winter and the ferocity of its heavy rains. During our over-long dry seasons, flood control is deemed their least pressing priority. Technion professors Naomi Carmon and Uri Shamir, of the Center of Urban and Regional Planning, turned their attention to this problem years ago. They produced a list of practical steps local and regional authorities can take. Based on these, the Interior Ministry issued its own rainwater-management directives in 2003. But few if any of these recommendations have been implemented. Quite the opposite. The record of transgressions against nature grows and aggravates the problem. Hod Hasharon is a case in point. One of its old neighborhoods, comprising low-slung houses constructed decades ago, was flooded twice last week alone. The loss isn't merely that of the homeowners, facing havoc in their living rooms, kitchens and bedrooms, but that of the national water economy, which is denied what cannot seep into the ground. For years, Hod Hasharon's old houses had no flooding problems. Then the municipality permitted the erection of large apartment complexes nearby. That meant roads, sidewalks, paved yards and parking lots. Construction altered the entire geo-system; rainwater couldn't penetrate the asphalt and began flowing straight to the smaller houses in its path. The city and contractors doubtless profited from the construction but evidently gave insufficient thought to the infrastructure and the creation of large non-porous surfaces. Different surfaces, including old-fashioned gravel, or even concrete slabs that leave some earth exposed between them, could have minimized the problem, along with properly planned inclines, sinkholes, parks, flower beds and playgrounds which, besides providing greenery, also offer porous surfaces. Of course, it's cheaper to build quickly without worrying about the consequences. In many other older neighborhoods, even within large cities, no rainwater drainage systems exist. At best the runoff is piped to sewers and precious water is lost. In some newer areas there are separate rainwater drainage facilities, although these are rarely well kept up. They are often clogged with fallen foliage and litter and aren't able to drain much of anything away from the gutters. Elsewhere, streets were plotted along creek beds, such as in southern Tel Aviv and Jaffa. Every now and then nature reminds heedless planners who ultimately has the upper hand. Many such vainglorious mistakes are long-standing. Nevertheless, even here drainage can still be improved. Those who remember old Wadi Mussrara in the 1950s aren't surprised that, renamed as Nahal Ayalon, it floods occasionally in winter and impedes traffic on the Ayalon Highway. The same goes for Nahariya's Ga'aton. There are no excuses for the failure to deal with this northern stream, which often rises over its banks. Nahariya city engineers know there are solutions. They just haven't been given the wherewithal to implement them. Even the water lost in ordinary apartment house yards after each rain-shower could, if conserved, significantly alleviate Israel's water shortage. The Technion researchers note that extremely simple remedies (like not allowing runoff from yards to flow out into the street, but forcing it via small, inexpensive retaining walls to seep through the soil) could do wonders for our national water balance, and for avoiding wasteful damaging floods. Such mind-set adjustments are every bit as necessary and as feasible as rooftop solar heaters once were. If we cease ignoring our short winters, we can benefit from them, rather than struggling to endure their caprice.